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Alan-Cox opened this issue Jan 25, 2012 · 1 comment
Closed

framebuffer code suggestions #4

Alan-Cox opened this issue Jan 25, 2012 · 1 comment

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@Alan-Cox
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  1. Your struct fbinfo_s uses int but in fact needs the bytes to precisely match the firmware interface. Also the values are in practice unsigned anyway, so use u32 to be clear
  2. Volatile - this wrecks your code generation and gcc in some releases has been known to get it rather wrong. If the firmware updates the block only when you ask it then you just need to add wmb(); before it and rmb(); after it to cover compiler temporaries. They provide write and read barriers instead of the mess the C language volatile makes.
  3. The code appears derived from the cirrusfb driver. That driver is copyrighted yet the copyright credits for the original have been stripped. We take such things very seriously, and stripping authorship credit is a GPL violation so this really wants a 'derived from ... etc' putting in by Broadcom. Nothing wrong with it being derived from and still GPL but the credit matters.
  4. ioremap on the screen base can fail. It's not clear what you should do in that case but it probably should at least BUG(), otherwise you'll have a screen at NULL so anyone making it fail can now patch low physical memory at will
  5. If you want the PI logo to get into the upstream you'll need to do it differently to hacking the existing logo
  6. You set various HWACCEL bits you don't have HWACCEL for ?
  7. General style - // comments, lots of printks that can go but appear to be still needed debug, pr_info etc not printk() and where possible dev_dbg() etc. lower case for the module arguments. Usually mundanities basically.
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
When a user with the CAP_SYS_RESOURCE cap tries to F_SETPIPE_SZ a pipe
with size bigger than kmalloc() can alloc it spits out an ugly warning:

  ------------[ cut here ]------------
  WARNING: at mm/page_alloc.c:2095 __alloc_pages_nodemask+0x5d3/0x7a0()
  Pid: 733, comm: a.out Not tainted 3.2.0-rc1+ raspberrypi#4
  Call Trace:
     warn_slowpath_common+0x75/0xb0
     warn_slowpath_null+0x15/0x20
     __alloc_pages_nodemask+0x5d3/0x7a0
     __get_free_pages+0x12/0x50
     __kmalloc+0x12b/0x150
     pipe_set_size+0x75/0x120
     pipe_fcntl+0xf8/0x140
     do_fcntl+0x2d4/0x410
     sys_fcntl+0x66/0xa0
     system_call_fastpath+0x16/0x1b
  ---[ end trace 432f702e6db7b5ee ]---

Instead, make kcalloc() handle the overflow case and fail quietly.

[[email protected]: switch to sizeof(*bufs) for 80-column niceness]
Signed-off-by: Sasha Levin <[email protected]>
Cc: Alexander Viro <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
LogFS uses super->s_write_mutex while writing data to disk. Taking the
same mutex lock in sync and fsync code path solves the following BUG:

------------[ cut here ]------------
kernel BUG at /home/prasad/logfs/dev_bdev.c:134!

Pid: 2387, comm: flush-253:16 Not tainted 3.0.0+ raspberrypi#4 Bochs Bochs
RIP: 0010:[<ffffffffa007deed>]  [<ffffffffa007deed>]
                bdev_writeseg+0x25d/0x270 [logfs]
Call Trace:
[<ffffffffa007c381>] logfs_open_area+0x91/0x150 [logfs]
[<ffffffff8128dcb2>] ? find_level.clone.9+0x62/0x100
[<ffffffffa007c49c>] __logfs_segment_write.clone.20+0x5c/0x190 [logfs]
[<ffffffff810ef005>] ? mempool_kmalloc+0x15/0x20
[<ffffffff810ef383>] ? mempool_alloc+0x53/0x130
[<ffffffffa007c7a4>] logfs_segment_write+0x1d4/0x230 [logfs]
[<ffffffffa0078f8e>] logfs_write_i0+0x12e/0x190 [logfs]
[<ffffffffa0079300>] __logfs_write_rec+0x140/0x220 [logfs]
[<ffffffffa0079444>] logfs_write_rec+0x64/0xd0 [logfs]
[<ffffffffa00795b6>] __logfs_write_buf+0x106/0x110 [logfs]
[<ffffffffa007a13e>] logfs_write_buf+0x4e/0x80 [logfs]
[<ffffffffa0073e33>] __logfs_writepage+0x23/0x80 [logfs]
[<ffffffffa007410c>] logfs_writepage+0xdc/0x110 [logfs]
[<ffffffff810f5ba7>] __writepage+0x17/0x40
[<ffffffff810f6208>] write_cache_pages+0x208/0x4f0
[<ffffffff810f5b90>] ? set_page_dirty+0x70/0x70
[<ffffffff810f653a>] generic_writepages+0x4a/0x70
[<ffffffff810f75d1>] do_writepages+0x21/0x40
[<ffffffff8116b9d1>] writeback_single_inode+0x101/0x250
[<ffffffff8116bdbd>] writeback_sb_inodes+0xed/0x1c0
[<ffffffff8116c5fb>] writeback_inodes_wb+0x7b/0x1e0
[<ffffffff8116cc23>] wb_writeback+0x4c3/0x530
[<ffffffff814d984d>] ? sub_preempt_count+0x9d/0xd0
[<ffffffff8116cd6b>] wb_do_writeback+0xdb/0x290
[<ffffffff814d984d>] ? sub_preempt_count+0x9d/0xd0
[<ffffffff814d6208>] ? _raw_spin_unlock_irqrestore+0x18/0x40
[<ffffffff8105aa5a>] ? del_timer+0x8a/0x120
[<ffffffff8116cfac>] bdi_writeback_thread+0x8c/0x2e0
[<ffffffff8116cf20>] ? wb_do_writeback+0x290/0x290
[<ffffffff8106d2e6>] kthread+0x96/0xa0
[<ffffffff814de514>] kernel_thread_helper+0x4/0x10
[<ffffffff8106d250>] ? kthread_worker_fn+0x190/0x190
[<ffffffff814de510>] ? gs_change+0xb/0xb
RIP  [<ffffffffa007deed>] bdev_writeseg+0x25d/0x270 [logfs]
---[ end trace 0211ad60a57657c4 ]---

Reviewed-by: Joern Engel <[email protected]>
Signed-off-by: Prasad Joshi <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
While unmounting the file system LogFS calls generic_shutdown_super.
The function does file system independent superblock shutdown.
However, it might result in call file system specific inode eviction.

LogFS marks FS shutting down by setting bit LOGFS_SB_FLAG_SHUTDOWN in
super->s_flags. Since, inode eviction might call truncate on inode,
following BUG is observed when file system is unmounted:

------------[ cut here ]------------
kernel BUG at /home/prasad/logfs/segment.c:362!
invalid opcode: 0000 [raspberrypi#1] PREEMPT SMP
CPU 3
Modules linked in: logfs binfmt_misc ppdev virtio_blk parport_pc lp
	parport psmouse floppy virtio_pci serio_raw virtio_ring virtio

Pid: 1933, comm: umount Not tainted 3.0.0+ raspberrypi#4 Bochs Bochs
RIP: 0010:[<ffffffffa008c841>]  [<ffffffffa008c841>]
		logfs_segment_write+0x211/0x230 [logfs]
RSP: 0018:ffff880062d7b9e8  EFLAGS: 00010202
RAX: 000000000000000e RBX: ffff88006eca9000 RCX: 0000000000000000
RDX: ffff88006fd87c40 RSI: ffffea00014ff468 RDI: ffff88007b68e000
RBP: ffff880062d7ba48 R08: 8000000020451430 R09: 0000000000000000
R10: dead000000100100 R11: 0000000000000000 R12: ffff88006fd87c40
R13: ffffea00014ff468 R14: ffff88005ad0a460 R15: 0000000000000000
FS:  00007f25d50ea760(0000) GS:ffff88007fd80000(0000)
	knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000d05e48 CR3: 0000000062c72000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount (pid: 1933, threadinfo ffff880062d7a000,
	task ffff880070b44500)
Stack:
ffff880062d7ba38 ffff88005ad0a508 0000000000001000 0000000000000000
8000000020451430 ffffea00014ff468 ffff880062d7ba48 ffff88005ad0a460
ffff880062d7bad8 ffffea00014ff468 ffff88006fd87c40 0000000000000000
Call Trace:
[<ffffffffa0088fee>] logfs_write_i0+0x12e/0x190 [logfs]
[<ffffffffa0089360>] __logfs_write_rec+0x140/0x220 [logfs]
[<ffffffffa0089312>] __logfs_write_rec+0xf2/0x220 [logfs]
[<ffffffffa00894a4>] logfs_write_rec+0x64/0xd0 [logfs]
[<ffffffffa0089616>] __logfs_write_buf+0x106/0x110 [logfs]
[<ffffffffa008a19e>] logfs_write_buf+0x4e/0x80 [logfs]
[<ffffffffa008a6b8>] __logfs_write_inode+0x98/0x110 [logfs]
[<ffffffffa008a7c4>] logfs_truncate+0x54/0x290 [logfs]
[<ffffffffa008abfc>] logfs_evict_inode+0xdc/0x190 [logfs]
[<ffffffff8115eef5>] evict+0x85/0x170
[<ffffffff8115f126>] iput+0xe6/0x1b0
[<ffffffff8115b4a8>] shrink_dcache_for_umount_subtree+0x218/0x280
[<ffffffff8115ce91>] shrink_dcache_for_umount+0x51/0x90
[<ffffffff8114796c>] generic_shutdown_super+0x2c/0x100
[<ffffffffa008cc47>] logfs_kill_sb+0x57/0xf0 [logfs]
[<ffffffff81147de5>] deactivate_locked_super+0x45/0x70
[<ffffffff811487ea>] deactivate_super+0x4a/0x70
[<ffffffff81163934>] mntput_no_expire+0xa4/0xf0
[<ffffffff8116469f>] sys_umount+0x6f/0x380
[<ffffffff814dd46b>] system_call_fastpath+0x16/0x1b
Code: 55 c8 49 8d b6 a8 00 00 00 45 89 f9 45 89 e8 4c 89 e1 4c 89 55
b8 c7 04 24 00 00 00 00 e8 68 fc ff ff 4c 8b 55 b8 e9 3c ff ff ff <0f>
0b 0f 0b c7 45 c0 00 00 00 00 e9 44 fe ff ff 66 66 66 66 66
RIP  [<ffffffffa008c841>] logfs_segment_write+0x211/0x230 [logfs]
RSP <ffff880062d7b9e8>
---[ end trace fe6b040cea952290 ]---

Therefore, move super->s_flags setting after the fs-indenpendent work
has been finished.

Reviewed-by: Joern Engel <[email protected]>
Signed-off-by: Prasad Joshi <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
There is no reason to hold hiddev->existancelock before
calling usb_deregister_dev, so move it out of the lock.

The patch fixes the lockdep warning below.

[ 5733.386271] ======================================================
[ 5733.386274] [ INFO: possible circular locking dependency detected ]
[ 5733.386278] 3.2.0-custom-next-20120111+ raspberrypi#1 Not tainted
[ 5733.386281] -------------------------------------------------------
[ 5733.386284] khubd/186 is trying to acquire lock:
[ 5733.386288]  (minor_rwsem){++++.+}, at: [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386311]
[ 5733.386312] but task is already holding lock:
[ 5733.386315]  (&hiddev->existancelock){+.+...}, at: [<ffffffffa0094d17>] hiddev_disconnect+0x26/0x87 [usbhid]
[ 5733.386328]
[ 5733.386329] which lock already depends on the new lock.
[ 5733.386330]
[ 5733.386333]
[ 5733.386334] the existing dependency chain (in reverse order) is:
[ 5733.386336]
[ 5733.386337] -> raspberrypi#1 (&hiddev->existancelock){+.+...}:
[ 5733.386346]        [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386357]        [<ffffffff813df961>] __mutex_lock_common+0x60/0x465
[ 5733.386366]        [<ffffffff813dfe4d>] mutex_lock_nested+0x36/0x3b
[ 5733.386371]        [<ffffffffa0094ad6>] hiddev_open+0x113/0x193 [usbhid]
[ 5733.386378]        [<ffffffffa0011971>] usb_open+0x66/0xc2 [usbcore]
[ 5733.386390]        [<ffffffff8111a8b5>] chrdev_open+0x12b/0x154
[ 5733.386402]        [<ffffffff811159a8>] __dentry_open.isra.16+0x20b/0x355
[ 5733.386408]        [<ffffffff811165dc>] nameidata_to_filp+0x43/0x4a
[ 5733.386413]        [<ffffffff81122ed5>] do_last+0x536/0x570
[ 5733.386419]        [<ffffffff8112300b>] path_openat+0xce/0x301
[ 5733.386423]        [<ffffffff81123327>] do_filp_open+0x33/0x81
[ 5733.386427]        [<ffffffff8111664d>] do_sys_open+0x6a/0xfc
[ 5733.386431]        [<ffffffff811166fb>] sys_open+0x1c/0x1e
[ 5733.386434]        [<ffffffff813e7c79>] system_call_fastpath+0x16/0x1b
[ 5733.386441]
[ 5733.386441] -> #0 (minor_rwsem){++++.+}:
[ 5733.386448]        [<ffffffff8108255d>] __lock_acquire+0xa80/0xd74
[ 5733.386454]        [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386458]        [<ffffffff813e01f5>] down_write+0x44/0x77
[ 5733.386464]        [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386475]        [<ffffffffa0094d2d>] hiddev_disconnect+0x3c/0x87 [usbhid]
[ 5733.386483]        [<ffffffff8132df51>] hid_disconnect+0x3f/0x54
[ 5733.386491]        [<ffffffff8132dfb4>] hid_device_remove+0x4e/0x7a
[ 5733.386496]        [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386502]        [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386507]        [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386512]        [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386519]        [<ffffffff8132def3>] hid_destroy_device+0x1e/0x3d
[ 5733.386525]        [<ffffffffa00916b0>] usbhid_disconnect+0x36/0x42 [usbhid]
[ 5733.386530]        [<ffffffffa000fb60>] usb_unbind_interface+0x57/0x11f [usbcore]
[ 5733.386542]        [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386547]        [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386552]        [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386557]        [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386562]        [<ffffffffa000de61>] usb_disable_device+0xa8/0x1d8 [usbcore]
[ 5733.386573]        [<ffffffffa0006bd2>] usb_disconnect+0xab/0x11f [usbcore]
[ 5733.386583]        [<ffffffffa0008aa0>] hub_thread+0x73b/0x1157 [usbcore]
[ 5733.386593]        [<ffffffff8105dc0f>] kthread+0x95/0x9d
[ 5733.386601]        [<ffffffff813e90b4>] kernel_thread_helper+0x4/0x10
[ 5733.386607]
[ 5733.386608] other info that might help us debug this:
[ 5733.386609]
[ 5733.386612]  Possible unsafe locking scenario:
[ 5733.386613]
[ 5733.386615]        CPU0                    CPU1
[ 5733.386618]        ----                    ----
[ 5733.386620]   lock(&hiddev->existancelock);
[ 5733.386625]                                lock(minor_rwsem);
[ 5733.386630]                                lock(&hiddev->existancelock);
[ 5733.386635]   lock(minor_rwsem);
[ 5733.386639]
[ 5733.386640]  *** DEADLOCK ***
[ 5733.386641]
[ 5733.386644] 6 locks held by khubd/186:
[ 5733.386646]  #0:  (&__lockdep_no_validate__){......}, at: [<ffffffffa00084af>] hub_thread+0x14a/0x1157 [usbcore]
[ 5733.386661]  raspberrypi#1:  (&__lockdep_no_validate__){......}, at: [<ffffffffa0006b77>] usb_disconnect+0x50/0x11f [usbcore]
[ 5733.386677]  raspberrypi#2:  (hcd->bandwidth_mutex){+.+.+.}, at: [<ffffffffa0006bc8>] usb_disconnect+0xa1/0x11f [usbcore]
[ 5733.386693]  raspberrypi#3:  (&__lockdep_no_validate__){......}, at: [<ffffffff812c09bb>] device_release_driver+0x18/0x2d
[ 5733.386704]  raspberrypi#4:  (&__lockdep_no_validate__){......}, at: [<ffffffff812c09bb>] device_release_driver+0x18/0x2d
[ 5733.386714]  raspberrypi#5:  (&hiddev->existancelock){+.+...}, at: [<ffffffffa0094d17>] hiddev_disconnect+0x26/0x87 [usbhid]
[ 5733.386727]
[ 5733.386727] stack backtrace:
[ 5733.386731] Pid: 186, comm: khubd Not tainted 3.2.0-custom-next-20120111+ raspberrypi#1
[ 5733.386734] Call Trace:
[ 5733.386741]  [<ffffffff81062881>] ? up+0x34/0x3b
[ 5733.386747]  [<ffffffff813d9ef3>] print_circular_bug+0x1f8/0x209
[ 5733.386752]  [<ffffffff8108255d>] __lock_acquire+0xa80/0xd74
[ 5733.386756]  [<ffffffff810808b4>] ? trace_hardirqs_on_caller+0x15d/0x1a3
[ 5733.386763]  [<ffffffff81043a3f>] ? vprintk+0x3f4/0x419
[ 5733.386774]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386779]  [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386789]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386797]  [<ffffffff813e01f5>] down_write+0x44/0x77
[ 5733.386807]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386818]  [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386825]  [<ffffffffa0094d2d>] hiddev_disconnect+0x3c/0x87 [usbhid]
[ 5733.386830]  [<ffffffff8132df51>] hid_disconnect+0x3f/0x54
[ 5733.386834]  [<ffffffff8132dfb4>] hid_device_remove+0x4e/0x7a
[ 5733.386839]  [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386844]  [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386848]  [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386854]  [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386859]  [<ffffffff8132def3>] hid_destroy_device+0x1e/0x3d
[ 5733.386865]  [<ffffffffa00916b0>] usbhid_disconnect+0x36/0x42 [usbhid]
[ 5733.386876]  [<ffffffffa000fb60>] usb_unbind_interface+0x57/0x11f [usbcore]
[ 5733.386882]  [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386886]  [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386890]  [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386895]  [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386905]  [<ffffffffa000de61>] usb_disable_device+0xa8/0x1d8 [usbcore]
[ 5733.386916]  [<ffffffffa0006bd2>] usb_disconnect+0xab/0x11f [usbcore]
[ 5733.386921]  [<ffffffff813dff82>] ? __mutex_unlock_slowpath+0x130/0x141
[ 5733.386929]  [<ffffffffa0008aa0>] hub_thread+0x73b/0x1157 [usbcore]
[ 5733.386935]  [<ffffffff8106a51d>] ? finish_task_switch+0x78/0x150
[ 5733.386941]  [<ffffffff8105e396>] ? __init_waitqueue_head+0x4c/0x4c
[ 5733.386950]  [<ffffffffa0008365>] ? usb_remote_wakeup+0x56/0x56 [usbcore]
[ 5733.386955]  [<ffffffff8105dc0f>] kthread+0x95/0x9d
[ 5733.386961]  [<ffffffff813e90b4>] kernel_thread_helper+0x4/0x10
[ 5733.386966]  [<ffffffff813e24b8>] ? retint_restore_args+0x13/0x13
[ 5733.386970]  [<ffffffff8105db7a>] ? __init_kthread_worker+0x55/0x55
[ 5733.386974]  [<ffffffff813e90b0>] ? gs_change+0x13/0x13

Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
…e atomic.

When a user offlines a VCPU and then onlines it, we get:

NMI watchdog disabled (cpu2): hardware events not enabled
BUG: scheduling while atomic: swapper/2/0/0x00000002
Modules linked in: dm_multipath dm_mod xen_evtchn iscsi_boot_sysfs iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi scsi_mod libcrc32c crc32c radeon fbco
 ttm bitblit softcursor drm_kms_helper xen_blkfront xen_netfront xen_fbfront fb_sys_fops sysimgblt sysfillrect syscopyarea xen_kbdfront xenfs [last unloaded:

Pid: 0, comm: swapper/2 Tainted: G           O 3.2.0phase15.1-00003-gd6f7f5b-dirty raspberrypi#4
Call Trace:
 [<ffffffff81070571>] __schedule_bug+0x61/0x70
 [<ffffffff8158eb78>] __schedule+0x798/0x850
 [<ffffffff8158ed6a>] schedule+0x3a/0x50
 [<ffffffff810349be>] cpu_idle+0xbe/0xe0
 [<ffffffff81583599>] cpu_bringup_and_idle+0xe/0x10

The reason for this should be obvious from this call-chain:
cpu_bringup_and_idle:
 \- cpu_bringup
  |   \-[preempt_disable]
  |
  |- cpu_idle
       \- play_dead [assuming the user offlined the VCPU]
       |     \
       |     +- (xen_play_dead)
       |          \- HYPERVISOR_VCPU_off [so VCPU is dead, once user
       |          |                       onlines it starts from here]
       |          \- cpu_bringup [preempt_disable]
       |
       +- preempt_enable_no_reschedule()
       +- schedule()
       \- preempt_enable()

So we have two preempt_disble() and one preempt_enable(). Calling
preempt_enable() after the cpu_bringup() in the xen_play_dead
fixes the imbalance.

Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
…S block during isolation for migration

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 raspberrypi#1 [d72d3b24] oops_end at c05c5322
 raspberrypi#2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 raspberrypi#3 [d72d3bec] bad_area at c0227fb6
 raspberrypi#4 [d72d3c00] do_page_fault at c05c72ec
 raspberrypi#5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 raspberrypi#6 [d72d3cb4] isolate_migratepages at c030b15a
 raspberrypi#7 [d72d3d14] zone_watermark_ok at c02d26cb
 raspberrypi#8 [d72d3d2c] compact_zone at c030b8d
 raspberrypi#9 [d72d3d68] compact_zone_order at c030bba1
raspberrypi#10 [d72d3db4] try_to_compact_pages at c030bc84
raspberrypi#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
raspberrypi#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
raspberrypi#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
raspberrypi#14 [d72d3eb8] alloc_pages_vma at c030a845
raspberrypi#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
raspberrypi#16 [d72d3f00] handle_mm_fault at c02f36c6
raspberrypi#17 [d72d3f30] do_page_fault at c05c70ed
raspberrypi#18 [d72d3fb] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 0000043
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <[email protected]>
Tested-by: Herbert van den Bergh <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
If the netdev is already in NETREG_UNREGISTERING/_UNREGISTERED state, do not
update the real num tx queues. netdev_queue_update_kobjects() is already
called via remove_queue_kobjects() at NETREG_UNREGISTERING time. So, when
upper layer driver, e.g., FCoE protocol stack is monitoring the netdev
event of NETDEV_UNREGISTER and calls back to LLD ndo_fcoe_disable() to remove
extra queues allocated for FCoE, the associated txq sysfs kobjects are already
removed, and trying to update the real num queues would cause something like
below:

...
PID: 25138  TASK: ffff88021e64c440  CPU: 3   COMMAND: "kworker/3:3"
 #0 [ffff88021f007760] machine_kexec at ffffffff810226d9
 raspberrypi#1 [ffff88021f0077d0] crash_kexec at ffffffff81089d2d
 raspberrypi#2 [ffff88021f0078a0] oops_end at ffffffff813bca78
 raspberrypi#3 [ffff88021f0078d0] no_context at ffffffff81029e72
 raspberrypi#4 [ffff88021f007920] __bad_area_nosemaphore at ffffffff8102a155
 raspberrypi#5 [ffff88021f0079f0] bad_area_nosemaphore at ffffffff8102a23e
 raspberrypi#6 [ffff88021f007a00] do_page_fault at ffffffff813bf32e
 raspberrypi#7 [ffff88021f007b10] page_fault at ffffffff813bc045
    [exception RIP: sysfs_find_dirent+17]
    RIP: ffffffff81178611  RSP: ffff88021f007bc0  RFLAGS: 00010246
    RAX: ffff88021e64c440  RBX: ffffffff8156cc63  RCX: 0000000000000004
    RDX: ffffffff8156cc63  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88021f007be0   R8: 0000000000000004   R9: 0000000000000008
    R10: ffffffff816fed00  R11: 0000000000000004  R12: 0000000000000000
    R13: ffffffff8156cc63  R14: 0000000000000000  R15: ffff8802222a0000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 raspberrypi#8 [ffff88021f007be8] sysfs_get_dirent at ffffffff81178c07
 raspberrypi#9 [ffff88021f007c18] sysfs_remove_group at ffffffff8117ac27
raspberrypi#10 [ffff88021f007c48] netdev_queue_update_kobjects at ffffffff813178f9
raspberrypi#11 [ffff88021f007c88] netif_set_real_num_tx_queues at ffffffff81303e38
raspberrypi#12 [ffff88021f007cc8] ixgbe_set_num_queues at ffffffffa0249763 [ixgbe]
raspberrypi#13 [ffff88021f007cf8] ixgbe_init_interrupt_scheme at ffffffffa024ea89 [ixgbe]
raspberrypi#14 [ffff88021f007d48] ixgbe_fcoe_disable at ffffffffa0267113 [ixgbe]
raspberrypi#15 [ffff88021f007d68] vlan_dev_fcoe_disable at ffffffffa014fef5 [8021q]
raspberrypi#16 [ffff88021f007d78] fcoe_interface_cleanup at ffffffffa02b7dfd [fcoe]
raspberrypi#17 [ffff88021f007df8] fcoe_destroy_work at ffffffffa02b7f08 [fcoe]
raspberrypi#18 [ffff88021f007e18] process_one_work at ffffffff8105d7ca
raspberrypi#19 [ffff88021f007e68] worker_thread at ffffffff81060513
raspberrypi#20 [ffff88021f007ee8] kthread at ffffffff810648b6
raspberrypi#21 [ffff88021f007f48] kernel_thread_helper at ffffffff813c40f4

Signed-off-by: Yi Zou <[email protected]>
Tested-by: Ross Brattain <[email protected]>
Tested-by: Stephen Ko <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>
bootc pushed a commit to bootc/linux-rpi-orig that referenced this issue May 8, 2012
…S block during isolation for migration

commit 0bf380b upstream.

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 raspberrypi#1 [d72d3b24] oops_end at c05c5322
 raspberrypi#2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 raspberrypi#3 [d72d3bec] bad_area at c0227fb6
 raspberrypi#4 [d72d3c00] do_page_fault at c05c72ec
 raspberrypi#5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 raspberrypi#6 [d72d3cb4] isolate_migratepages at c030b15a
 raspberrypi#7 [d72d3d14] zone_watermark_ok at c02d26cb
 raspberrypi#8 [d72d3d2c] compact_zone at c030b8d
 raspberrypi#9 [d72d3d68] compact_zone_order at c030bba1
raspberrypi#10 [d72d3db4] try_to_compact_pages at c030bc84
raspberrypi#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
raspberrypi#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
raspberrypi#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
raspberrypi#14 [d72d3eb8] alloc_pages_vma at c030a845
raspberrypi#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
raspberrypi#16 [d72d3f00] handle_mm_fault at c02f36c6
raspberrypi#17 [d72d3f30] do_page_fault at c05c70ed
raspberrypi#18 [d72d3fb] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 0000043
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <[email protected]>
Tested-by: Herbert van den Bergh <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012
…condition

commit 26c1917 upstream.

When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 raspberrypi#1 [f06a9e2c] oops_end at c083d1c2
 raspberrypi#2 [f06a9e40] no_context at c0433ded
 raspberrypi#3 [f06a9e64] bad_area_nosemaphore at c043401a
 raspberrypi#4 [f06a9e6c] __do_page_fault at c0434493
 raspberrypi#5 [f06a9eec] do_page_fault at c083eb45
 raspberrypi#6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 raspberrypi#7 [f06a9f38] _spin_lock at c083bc14
 raspberrypi#8 [f06a9f44] sys_mincore at c0507b7d
 raspberrypi#9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Larry Woodman <[email protected]>
Cc: Petr Matousek <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012
commit 2c0c2a0 upstream.

While traversing the linked list of open file handles, if the identfied
file handle is invalid, a reopen is attempted and if it fails, we
resume traversing where we stopped and cifs can oops while accessing
invalid next element, for list might have changed.

So mark the invalid file handle and attempt reopen if no
valid file handle is found in rest of the list.
If reopen fails, move the invalid file handle to the end of the list
and start traversing the list again from the begining.
Repeat this four times before giving up and returning an error if
file reopen keeps failing.

Signed-off-by: Shirish Pargaonkar <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
ladyada referenced this issue in adafruit/adafruit-raspberrypi-linux Aug 1, 2012
popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012
commit 3cf003c upstream.

Jian found that when he ran fsx on a 32 bit arch with a large wsize the
process and one of the bdi writeback kthreads would sometimes deadlock
with a stack trace like this:

crash> bt
PID: 2789   TASK: f02edaa0  CPU: 3   COMMAND: "fsx"
 #0 [eed63cbc] schedule at c083c5b3
 raspberrypi#1 [eed63d80] kmap_high at c0500ec8
 raspberrypi#2 [eed63db0] cifs_async_writev at f7fabcd7 [cifs]
 raspberrypi#3 [eed63df0] cifs_writepages at f7fb7f5c [cifs]
 raspberrypi#4 [eed63e50] do_writepages at c04f3e32
 raspberrypi#5 [eed63e54] __filemap_fdatawrite_range at c04e152a
 raspberrypi#6 [eed63ea4] filemap_fdatawrite at c04e1b3e
 raspberrypi#7 [eed63eb4] cifs_file_aio_write at f7fa111a [cifs]
 raspberrypi#8 [eed63ecc] do_sync_write at c052d202
 raspberrypi#9 [eed63f74] vfs_write at c052d4ee
raspberrypi#10 [eed63f94] sys_write at c052df4c
raspberrypi#11 [eed63fb0] ia32_sysenter_target at c0409a98
    EAX: 00000004  EBX: 00000003  ECX: abd73b73  EDX: 012a65c6
    DS:  007b      ESI: 012a65c6  ES:  007b      EDI: 00000000
    SS:  007b      ESP: bf8db178  EBP: bf8db1f8  GS:  0033
    CS:  0073      EIP: 40000424  ERR: 00000004  EFLAGS: 00000246

Each task would kmap part of its address array before getting stuck, but
not enough to actually issue the write.

This patch fixes this by serializing the marshal_iov operations for
async reads and writes. The idea here is to ensure that cifs
aggressively tries to populate a request before attempting to fulfill
another one. As soon as all of the pages are kmapped for a request, then
we can unlock and allow another one to proceed.

There's no need to do this serialization on non-CONFIG_HIGHMEM arches
however, so optimize all of this out when CONFIG_HIGHMEM isn't set.

Reported-by: Jian Li <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <[email protected]>
popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012
…d reasons

commit 5cf02d0 upstream.

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     raspberrypi#1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     raspberrypi#2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     raspberrypi#3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     raspberrypi#4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     raspberrypi#5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     raspberrypi#6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     raspberrypi#7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     raspberrypi#8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     raspberrypi#9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    raspberrypi#10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    raspberrypi#11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    raspberrypi#12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    raspberrypi#13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    raspberrypi#14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    raspberrypi#15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    raspberrypi#16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    raspberrypi#17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    raspberrypi#18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    raspberrypi#19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    raspberrypi#20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    raspberrypi#21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    raspberrypi#22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    raspberrypi#23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    raspberrypi#24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    raspberrypi#25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Ben Hutchings <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Printing the "start_ip" for every secondary cpu is very noisy on a large
system - and doesn't add any value. Drop this message.

Console log before:
Booting Node   0, Processors  #1
smpboot cpu 1: start_ip = 96000
 #2
smpboot cpu 2: start_ip = 96000
 #3
smpboot cpu 3: start_ip = 96000
 #4
smpboot cpu 4: start_ip = 96000
       ...
 #31
smpboot cpu 31: start_ip = 96000
Brought up 32 CPUs

Console log after:
Booting Node   0, Processors  #1 #2 #3 #4 #5 #6 #7 Ok.
Booting Node   1, Processors  #8 #9 #10 #11 #12 #13 #14 #15 Ok.
Booting Node   0, Processors  #16 #17 #18 #19 #20 #21 #22 #23 Ok.
Booting Node   1, Processors  #24 #25 #26 #27 #28 #29 #30 #31
Brought up 32 CPUs

Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Tony Luck <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Remove individual platform header files for dm365, dm355, dm644x
and dm646x and consolidate it into a single and common
header file davinci.h placed in arch/arm/mach-davinci.

This reduces the pollution in the include/mach and is consistent
with Russell's suggestions as part of his "pet peaves" mail.
(See #4 in: http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/071516.html)

While at it, fix the forward declaration of spi_board_info,
and include the right header file instead.

The further patches in the series take  advantage of this consolidation
for easy implementation of IO_ADDRESS elimination.

Signed-off-by: Manjunath Hadli <[email protected]>
[[email protected]: make davinci.h the first local include file,
fix forward declaration of spi_board_info and add back Deep Root
Systems, LLC copyright]
Signed-off-by: Sekhar Nori <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The <linux/device.h> header includes a lot of stuff, and
it in turn gets a lot of use just for the basic "struct device"
which appears so often.

Clean up the users as follows:

1) For those headers only needing "struct device" as a pointer
in fcn args, replace the include with exactly that.

2) For headers not really using anything from device.h, simply
delete the include altogether.

3) For headers relying on getting device.h implicitly before
being included themselves, now explicitly include device.h

4) For files in which doing #1 or #2 uncovers an implicit
dependency on some other header, fix by explicitly adding
the required header(s).

Any C files that were implicitly relying on device.h to be
present have already been dealt with in advance.

Total removals from #1 and #2: 51.  Total additions coming
from #3: 9.  Total other implicit dependencies from #4: 7.

As of 3.3-rc1, there were 110, so a net removal of 42 gives
about a 38% reduction in device.h presence in include/*

Signed-off-by: Paul Gortmaker <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The compiler does not conditionalize the assembly instructions for
the tlb operations, which leads to sub-optimal code being generated
when building a kernel for multiple CPUs.

We can tweak things fairly simply as the code fragment below shows:

    17f8:       e3120001        tst     r2, #1  ; 0x1
...
    1800:       0a000000        beq     1808 <handle_pte_fault+0x194>
    1804:       ee061f10        mcr     15, 0, r1, cr6, cr0, {0}
    1808:       e3120004        tst     r2, #4  ; 0x4
    180c:       0a000000        beq     1814 <handle_pte_fault+0x1a0>
    1810:       ee081f36        mcr     15, 0, r1, cr8, cr6, {1}
becomes:
    17f0:       e3120001        tst     r2, #1  ; 0x1
    17f4:       1e063f1        mcrne   15, 0, r3, cr6, cr0, {0}
    17f8:       e3120004        tst     r2, #4  ; 0x4
    17fc:       1e083f36        mcrne   15, 0, r3, cr8, cr6, {1}

Overall, for Realview with V6 and V7 CPUs configured:

   text    data     bss     dec     hex filename
4153998  207340 5371036 9732374  948116 ../build/realview/vmlinux.before
4153366  207332 5371036 9731734  947e96 ../build/realview/vmlinux.after

Signed-off-by: Russell King <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The ID used for detection of the BenQ R55E actually identifies the
Quanta TW3 ODM design, which is also used for the Gigabyte W551 laptop
series. Schematics on the internet clearly indicate that the "Port C"
(analog input connected to record source #4 and mixer input #4) is
unconnected.

Playing an audio CD through analog playback (using cdplay from cdtools)
produces no sound, even with the mixer input labelled "CD" enabled, and
the volume control in the CD drive set to maximum. This indicates the
connection is really not present.

Signed-off-by: Michael Karcher <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The following lockdep problem was reported by Or Gerlitz <[email protected]>:

    [ INFO: possible recursive locking detected ]
    3.3.0-32035-g1b2649e-dirty #4 Not tainted
    ---------------------------------------------
    kworker/5:1/418 is trying to acquire lock:
     (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0138a41>] rdma_destroy_i    d+0x33/0x1f0 [rdma_cm]

    but task is already holding lock:
     (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disable_ca    llback+0x24/0x45 [rdma_cm]

    other info that might help us debug this:
     Possible unsafe locking scenario:

           CPU0
           ----
      lock(&id_priv->handler_mutex);
      lock(&id_priv->handler_mutex);

     *** DEADLOCK ***

     May be due to missing lock nesting notation

    3 locks held by kworker/5:1/418:
     #0:  (ib_cm){.+.+.+}, at: [<ffffffff81042ac1>] process_one_work+0x210/0x4a    6
     #1:  ((&(&work->work)->work)){+.+.+.}, at: [<ffffffff81042ac1>] process_on    e_work+0x210/0x4a6
     #2:  (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disab    le_callback+0x24/0x45 [rdma_cm]

    stack backtrace:
    Pid: 418, comm: kworker/5:1 Not tainted 3.3.0-32035-g1b2649e-dirty #4
    Call Trace:
     [<ffffffff8102b0fb>] ? console_unlock+0x1f4/0x204
     [<ffffffff81068771>] __lock_acquire+0x16b5/0x174e
     [<ffffffff8106461f>] ? save_trace+0x3f/0xb3
     [<ffffffff810688fa>] lock_acquire+0xf0/0x116
     [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffff81364351>] mutex_lock_nested+0x64/0x2ce
     [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155
     [<ffffffff81065abc>] ? trace_hardirqs_on+0xd/0xf
     [<ffffffffa0138a41>] rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffffa0139c02>] cma_req_handler+0x418/0x644 [rdma_cm]
     [<ffffffffa012ee88>] cm_process_work+0x32/0x119 [ib_cm]
     [<ffffffffa0130299>] cm_req_handler+0x928/0x982 [ib_cm]
     [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm]
     [<ffffffffa0130326>] cm_work_handler+0x33/0xfe5 [ib_cm]
     [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155
     [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm]
     [<ffffffff81042b6e>] process_one_work+0x2bd/0x4a6
     [<ffffffff81042ac1>] ? process_one_work+0x210/0x4a6
     [<ffffffff813669f3>] ? _raw_spin_unlock_irq+0x2b/0x40
     [<ffffffff8104316e>] worker_thread+0x1d6/0x350
     [<ffffffff81042f98>] ? rescuer_thread+0x241/0x241
     [<ffffffff81046a32>] kthread+0x84/0x8c
     [<ffffffff8136e854>] kernel_thread_helper+0x4/0x10
     [<ffffffff81366d59>] ? retint_restore_args+0xe/0xe
     [<ffffffff810469ae>] ? __init_kthread_worker+0x56/0x56
     [<ffffffff8136e850>] ? gs_change+0xb/0xb

The actual locking is fine, since we're dealing with different locks,
but from the same lock class.  cma_disable_callback() acquires the
listening id mutex, whereas rdma_destroy_id() acquires the mutex for
the new connection id.  To fix this, delay the call to
rdma_destroy_id() until we've released the listening id mutex.

Signed-off-by: Sean Hefty <[email protected]>
Signed-off-by: Roland Dreier <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
platform_device pdev can be NULL if CONFIG_MMC_OMAP_HS is not set.
Add check for NULL pointer. while at it move the duplicated functions
to omap4-common.c

Fixes the following boot crash seen with omap4sdp and omap4panda
when MMC is disabled.

Unable to handle kernel NULL pointer dereference at virtual address 0000008
pgd = c0004000
[0000008] *pgd=00000000
Internal error: Oops: 5 [#1] SMP ARM
Modules linked in:
CPU: 0    Not tainted  (3.4.0-rc1-05971-ga4dfa82 #4)
PC is at omap_4430sdp_init+0x184/0x410
LR is at device_add+0x1a0/0x664

Signed-off-by: Balaji T K <[email protected]>
Reported-by: Santosh Shilimkar <[email protected]>
Signed-off-by: Tony Lindgren <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
xfs_sync_worker checks the MS_ACTIVE flag in s_flags to avoid doing
work during mount and unmount.  This flag can be cleared by unmount
after the xfs_sync_worker checks it but before the work is completed.
The has caused crashes in the completion handler for the dummy
transaction commited by xfs_sync_worker:

PID: 27544  TASK: ffff88013544e040  CPU: 3   COMMAND: "kworker/3:0"
 #0 [ffff88016fdff930] machine_kexec at ffffffff810244e9
 #1 [ffff88016fdff9a0] crash_kexec at ffffffff8108d053
 #2 [ffff88016fdffa70] oops_end at ffffffff813ad1b8
 #3 [ffff88016fdffaa0] no_context at ffffffff8102bd48
 #4 [ffff88016fdffaf0] __bad_area_nosemaphore at ffffffff8102c04d
 #5 [ffff88016fdffb40] bad_area_nosemaphore at ffffffff8102c12e
 #6 [ffff88016fdffb50] do_page_fault at ffffffff813afaee
 #7 [ffff88016fdffc60] page_fault at ffffffff813ac635
    [exception RIP: xlog_get_lowest_lsn+0x30]
    RIP: ffffffffa04a9910  RSP: ffff88016fdffd10  RFLAGS: 00010246
    RAX: ffffc90014e48000  RBX: ffff88014d879980  RCX: ffff88014d879980
    RDX: ffff8802214ee4c0  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88016fdffd10   R8: ffff88014d879a80   R9: 0000000000000000
    R10: 0000000000000001  R11: 0000000000000000  R12: ffff8802214ee400
    R13: ffff88014d879980  R14: 0000000000000000  R15: ffff88022fd96605
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffff88016fdffd18] xlog_state_do_callback at ffffffffa04aa186 [xfs]
 #9 [ffff88016fdffd98] xlog_state_done_syncing at ffffffffa04aa568 [xfs]

Protect xfs_sync_worker by using the s_umount semaphore at the read
level to provide exclusion with unmount while work is progressing.

Reviewed-by: Mark Tinguely <[email protected]>
Signed-off-by: Ben Myers <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
While traversing the linked list of open file handles, if the identfied
file handle is invalid, a reopen is attempted and if it fails, we
resume traversing where we stopped and cifs can oops while accessing
invalid next element, for list might have changed.

So mark the invalid file handle and attempt reopen if no
valid file handle is found in rest of the list.
If reopen fails, move the invalid file handle to the end of the list
and start traversing the list again from the begining.
Repeat this four times before giving up and returning an error if
file reopen keeps failing.

Cc: <[email protected]>
Signed-off-by: Shirish Pargaonkar <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Pull CIFS updates from Steve French.

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6: (29 commits)
  cifs: fix oops while traversing open file list (try #4)
  cifs: Fix comment as d_alloc_root() is replaced by d_make_root()
  CIFS: Introduce SMB2 mounts as vers=2.1
  CIFS: Introduce SMB2 Kconfig option
  CIFS: Move add/set_credits and get_credits_field to ops structure
  CIFS: Move protocol specific demultiplex thread calls to ops struct
  CIFS: Move protocol specific part from cifs_readv_receive to ops struct
  CIFS: Move header_size/max_header_size to ops structure
  CIFS: Move protocol specific part from SendReceive2 to ops struct
  cifs: Include backup intent search flags during searches {try #2)
  CIFS: Separate protocol specific part from setlk
  CIFS: Separate protocol specific part from getlk
  CIFS: Separate protocol specific lock type handling
  CIFS: Convert lock type to 32 bit variable
  CIFS: Move locks to cifsFileInfo structure
  cifs: convert send_nt_cancel into a version specific op
  cifs: add a smb_version_operations/values structures and a smb_version enum
  cifs: remove the vers= and version= synonyms for ver=
  cifs: add warning about change in default cache semantics in 3.7
  cifs: display cache= option in /proc/mounts
  ...
popcornmix pushed a commit that referenced this issue Oct 13, 2012
…condition

When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 #1 [f06a9e2c] oops_end at c083d1c2
 #2 [f06a9e40] no_context at c0433ded
 #3 [f06a9e64] bad_area_nosemaphore at c043401a
 #4 [f06a9e6c] __do_page_fault at c0434493
 #5 [f06a9eec] do_page_fault at c083eb45
 #6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 #7 [f06a9f38] _spin_lock at c083bc14
 #8 [f06a9f44] sys_mincore at c0507b7d
 #9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Larry Woodman <[email protected]>
Cc: Petr Matousek <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Remove spinlock as atomic_t can be used instead. Note we use only 16
lower bits, upper bits are changed but we impilcilty cast to u16.

This fix possible deadlock on IBSS mode reproted by lockdep:

=================================
[ INFO: inconsistent lock state ]
3.4.0-wl+ #4 Not tainted
---------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&(&intf->seqlock)->rlock){+.?...}, at: [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
{IN-SOFTIRQ-W} state was registered at:
  [<c04978ab>] __lock_acquire+0x47b/0x1050
  [<c0498504>] lock_acquire+0x84/0xf0
  [<c0835733>] _raw_spin_lock+0x33/0x40
  [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
  [<f9979f2a>] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
  [<f997834f>] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
  [<f98fe363>] __ieee80211_tx+0x1b3/0x300 [mac80211]
  [<f98ffdf5>] ieee80211_tx+0x105/0x130 [mac80211]
  [<f99000dd>] ieee80211_xmit+0xad/0x100 [mac80211]
  [<f9900519>] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
  [<c0782e87>] dev_hard_start_xmit+0x307/0x660
  [<c079bb71>] sch_direct_xmit+0xa1/0x1e0
  [<c0784bb3>] dev_queue_xmit+0x183/0x730
  [<c078c27a>] neigh_resolve_output+0xfa/0x1e0
  [<c07b436a>] ip_finish_output+0x24a/0x460
  [<c07b4897>] ip_output+0xb7/0x100
  [<c07b2d60>] ip_local_out+0x20/0x60
  [<c07e01ff>] igmpv3_sendpack+0x4f/0x60
  [<c07e108f>] igmp_ifc_timer_expire+0x29f/0x330
  [<c04520fc>] run_timer_softirq+0x15c/0x2f0
  [<c0449e3e>] __do_softirq+0xae/0x1e0
irq event stamp: 18380437
hardirqs last  enabled at (18380437): [<c0526027>] __slab_alloc.clone.3+0x67/0x5f0
hardirqs last disabled at (18380436): [<c0525ff3>] __slab_alloc.clone.3+0x33/0x5f0
softirqs last  enabled at (18377616): [<c0449eb3>] __do_softirq+0x123/0x1e0
softirqs last disabled at (18377611): [<c041278d>] do_softirq+0x9d/0xe0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&intf->seqlock)->rlock);
  <Interrupt>
    lock(&(&intf->seqlock)->rlock);

 *** DEADLOCK ***

4 locks held by kworker/u:2/30374:
 #0:  (wiphy_name(local->hw.wiphy)){++++.+}, at: [<c045cf99>] process_one_work+0x109/0x3f0
 #1:  ((&sdata->work)){+.+.+.}, at: [<c045cf99>] process_one_work+0x109/0x3f0
 #2:  (&ifibss->mtx){+.+.+.}, at: [<f98f005b>] ieee80211_ibss_work+0x1b/0x470 [mac80211]
 #3:  (&intf->beacon_skb_mutex){+.+...}, at: [<f997a644>] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]

stack backtrace:
Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
Call Trace:
 [<c04962a6>] print_usage_bug+0x1f6/0x220
 [<c0496a12>] mark_lock+0x2c2/0x300
 [<c0495ff0>] ? check_usage_forwards+0xc0/0xc0
 [<c04978ec>] __lock_acquire+0x4bc/0x1050
 [<c0527890>] ? __kmalloc_track_caller+0x1c0/0x1d0
 [<c0777fb6>] ? copy_skb_header+0x26/0x90
 [<c0498504>] lock_acquire+0x84/0xf0
 [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<c0835733>] _raw_spin_lock+0x33/0x40
 [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<f997a5cf>] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
 [<f997a64d>] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
 [<f9977e3a>] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
 [<f9977c70>] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
 [<f98e4dd0>] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
 [<f98ef7b8>] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
 [<c0496ab4>] ? mark_held_locks+0x64/0xc0
 [<c0440012>] ? virt_efi_query_capsule_caps+0x12/0x50
 [<f98efb09>] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
 [<f98f0456>] ieee80211_ibss_work+0x416/0x470 [mac80211]
 [<c0496d8b>] ? trace_hardirqs_on+0xb/0x10
 [<c077683b>] ? skb_dequeue+0x4b/0x70
 [<f98f207f>] ieee80211_iface_work+0x13f/0x230 [mac80211]
 [<c045cf99>] ? process_one_work+0x109/0x3f0
 [<c045d015>] process_one_work+0x185/0x3f0
 [<c045cf99>] ? process_one_work+0x109/0x3f0
 [<f98f1f40>] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
 [<c045ed86>] worker_thread+0x116/0x270
 [<c045ec70>] ? manage_workers+0x1e0/0x1e0
 [<c0462f64>] kthread+0x84/0x90
 [<c0462ee0>] ? __init_kthread_worker+0x60/0x60
 [<c083d382>] kernel_thread_helper+0x6/0x10

Cc: [email protected]
Signed-off-by: Stanislaw Gruszka <[email protected]>
Acked-by: Helmut Schaa <[email protected]>
Acked-by: Gertjan van Wingerde <[email protected]>
Signed-off-by: John W. Linville <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The warning below triggers on AMD MCM packages because physical package
IDs on the cores of a _physical_ socket are the same. I.e., this field
says which CPUs belong to the same physical package.

However, the same two CPUs belong to two different internal, i.e.
"logical" nodes in the same physical socket which is reflected in the
CPU-to-node map on x86 with NUMA.

Which makes this check wrong on the above topologies so circumvent it.

[    0.444413] Booting Node   0, Processors  #1 #2 #3 #4 #5 Ok.
[    0.461388] ------------[ cut here ]------------
[    0.465997] WARNING: at arch/x86/kernel/smpboot.c:310 topology_sane.clone.1+0x6e/0x81()
[    0.473960] Hardware name: Dinar
[    0.477170] sched: CPU #6's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
[    0.486860] Booting Node   1, Processors  #6
[    0.491104] Modules linked in:
[    0.494141] Pid: 0, comm: swapper/6 Not tainted 3.4.0+ #1
[    0.499510] Call Trace:
[    0.501946]  [<ffffffff8144bf92>] ? topology_sane.clone.1+0x6e/0x81
[    0.508185]  [<ffffffff8102f1fc>] warn_slowpath_common+0x85/0x9d
[    0.514163]  [<ffffffff8102f2b7>] warn_slowpath_fmt+0x46/0x48
[    0.519881]  [<ffffffff8144bf92>] topology_sane.clone.1+0x6e/0x81
[    0.525943]  [<ffffffff8144c234>] set_cpu_sibling_map+0x251/0x371
[    0.532004]  [<ffffffff8144c4ee>] start_secondary+0x19a/0x218
[    0.537729] ---[ end trace 4eaa2a86a8e2da22 ]---
[    0.628197]  #7 #8 #9 #10 #11 Ok.
[    0.807108] Booting Node   3, Processors  #12 #13 #14 #15 #16 #17 Ok.
[    0.897587] Booting Node   2, Processors  #18 #19 #20 #21 #22 #23 Ok.
[    0.917443] Brought up 24 CPUs

We ran a topology sanity check test we have here on it and
it all looks ok... hopefully :).

Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andreas Herrmann <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
1. removed code replication for tov calculation for 1G, 10G and
made is common for speed > 1G (1G, 10G, 40G, 100G).
2. defines values for #4 different 40G Phys (KR4, LF4, SR4, CR4)

Signed-off-by: Parav Pandit <[email protected]>
Reviewed-by: Ben Hutchings <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Jian found that when he ran fsx on a 32 bit arch with a large wsize the
process and one of the bdi writeback kthreads would sometimes deadlock
with a stack trace like this:

crash> bt
PID: 2789   TASK: f02edaa0  CPU: 3   COMMAND: "fsx"
 #0 [eed63cbc] schedule at c083c5b3
 #1 [eed63d80] kmap_high at c0500ec8
 #2 [eed63db0] cifs_async_writev at f7fabcd7 [cifs]
 #3 [eed63df0] cifs_writepages at f7fb7f5c [cifs]
 #4 [eed63e50] do_writepages at c04f3e32
 #5 [eed63e54] __filemap_fdatawrite_range at c04e152a
 #6 [eed63ea4] filemap_fdatawrite at c04e1b3e
 #7 [eed63eb4] cifs_file_aio_write at f7fa111a [cifs]
 #8 [eed63ecc] do_sync_write at c052d202
 #9 [eed63f74] vfs_write at c052d4ee
#10 [eed63f94] sys_write at c052df4c
#11 [eed63fb0] ia32_sysenter_target at c0409a98
    EAX: 00000004  EBX: 00000003  ECX: abd73b73  EDX: 012a65c6
    DS:  007b      ESI: 012a65c6  ES:  007b      EDI: 00000000
    SS:  007b      ESP: bf8db178  EBP: bf8db1f8  GS:  0033
    CS:  0073      EIP: 40000424  ERR: 00000004  EFLAGS: 00000246

Each task would kmap part of its address array before getting stuck, but
not enough to actually issue the write.

This patch fixes this by serializing the marshal_iov operations for
async reads and writes. The idea here is to ensure that cifs
aggressively tries to populate a request before attempting to fulfill
another one. As soon as all of the pages are kmapped for a request, then
we can unlock and allow another one to proceed.

There's no need to do this serialization on non-CONFIG_HIGHMEM arches
however, so optimize all of this out when CONFIG_HIGHMEM isn't set.

Cc: <[email protected]>
Reported-by: Jian Li <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
…d reasons

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    #24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Cc: [email protected]
popcornmix pushed a commit that referenced this issue Oct 13, 2012
On architectures where cputime_t is 64 bit type, is possible to trigger
divide by zero on do_div(temp, (__force u32) total) line, if total is a
non zero number but has lower 32 bit's zeroed. Removing casting is not
a good solution since some do_div() implementations do cast to u32
internally.

This problem can be triggered in practice on very long lived processes:

  PID: 2331   TASK: ffff880472814b00  CPU: 2   COMMAND: "oraagent.bin"
   #0 [ffff880472a51b70] machine_kexec at ffffffff8103214b
   #1 [ffff880472a51bd0] crash_kexec at ffffffff810b91c2
   #2 [ffff880472a51ca0] oops_end at ffffffff814f0b00
   #3 [ffff880472a51cd0] die at ffffffff8100f26b
   #4 [ffff880472a51d00] do_trap at ffffffff814f03f4
   #5 [ffff880472a51d60] do_divide_error at ffffffff8100cfff
   #6 [ffff880472a51e00] divide_error at ffffffff8100be7b
      [exception RIP: thread_group_times+0x56]
      RIP: ffffffff81056a16  RSP: ffff880472a51eb8  RFLAGS: 00010046
      RAX: bc3572c9fe12d194  RBX: ffff880874150800  RCX: 0000000110266fad
      RDX: 0000000000000000  RSI: ffff880472a51eb8  RDI: 001038ae7d9633dc
      RBP: ffff880472a51ef8   R8: 00000000b10a3a64   R9: ffff880874150800
      R10: 00007fcba27ab680  R11: 0000000000000202  R12: ffff880472a51f08
      R13: ffff880472a51f10  R14: 0000000000000000  R15: 0000000000000007
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffff880472a51f00] do_sys_times at ffffffff8108845d
   #8 [ffff880472a51f40] sys_times at ffffffff81088524
   #9 [ffff880472a51f80] system_call_fastpath at ffffffff8100b0f2
      RIP: 0000003808caac3a  RSP: 00007fcba27ab6d8  RFLAGS: 00000202
      RAX: 0000000000000064  RBX: ffffffff8100b0f2  RCX: 0000000000000000
      RDX: 00007fcba27ab6e0  RSI: 000000000076d58e  RDI: 00007fcba27ab6e0
      RBP: 00007fcba27ab700   R8: 0000000000000020   R9: 000000000000091b
      R10: 00007fcba27ab680  R11: 0000000000000202  R12: 00007fff9ca41940
      R13: 0000000000000000  R14: 00007fcba27ac9c0  R15: 00007fff9ca41940
      ORIG_RAX: 0000000000000064  CS: 0033  SS: 002b

Cc: [email protected]
Signed-off-by: Stanislaw Gruszka <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 10, 2025
[ Upstream commit 053f3ff ]

v2:
- Created a single error handling unlock and exit in veth_pool_store
- Greatly expanded commit message with previous explanatory-only text

Summary: Use rtnl_mutex to synchronize veth_pool_store with itself,
ibmveth_close and ibmveth_open, preventing multiple calls in a row to
napi_disable.

Background: Two (or more) threads could call veth_pool_store through
writing to /sys/devices/vio/30000002/pool*/*. You can do this easily
with a little shell script. This causes a hang.

I configured LOCKDEP, compiled ibmveth.c with DEBUG, and built a new
kernel. I ran this test again and saw:

    Setting pool0/active to 0
    Setting pool1/active to 1
    [   73.911067][ T4365] ibmveth 30000002 eth0: close starting
    Setting pool1/active to 1
    Setting pool1/active to 0
    [   73.911367][ T4366] ibmveth 30000002 eth0: close starting
    [   73.916056][ T4365] ibmveth 30000002 eth0: close complete
    [   73.916064][ T4365] ibmveth 30000002 eth0: open starting
    [  110.808564][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  230.808495][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  243.683786][  T123] INFO: task stress.sh:4365 blocked for more than 122 seconds.
    [  243.683827][  T123]       Not tainted 6.14.0-01103-g2df0c02dab82-dirty #8
    [  243.683833][  T123] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    [  243.683838][  T123] task:stress.sh       state:D stack:28096 pid:4365  tgid:4365  ppid:4364   task_flags:0x400040 flags:0x00042000
    [  243.683852][  T123] Call Trace:
    [  243.683857][  T123] [c00000000c38f690] [0000000000000001] 0x1 (unreliable)
    [  243.683868][  T123] [c00000000c38f840] [c00000000001f908] __switch_to+0x318/0x4e0
    [  243.683878][  T123] [c00000000c38f8a0] [c000000001549a70] __schedule+0x500/0x12a0
    [  243.683888][  T123] [c00000000c38f9a0] [c00000000154a878] schedule+0x68/0x210
    [  243.683896][  T123] [c00000000c38f9d0] [c00000000154ac80] schedule_preempt_disabled+0x30/0x50
    [  243.683904][  T123] [c00000000c38fa00] [c00000000154dbb0] __mutex_lock+0x730/0x10f0
    [  243.683913][  T123] [c00000000c38fb10] [c000000001154d40] napi_enable+0x30/0x60
    [  243.683921][  T123] [c00000000c38fb40] [c000000000f4ae94] ibmveth_open+0x68/0x5dc
    [  243.683928][  T123] [c00000000c38fbe0] [c000000000f4aa20] veth_pool_store+0x220/0x270
    [  243.683936][  T123] [c00000000c38fc70] [c000000000826278] sysfs_kf_write+0x68/0xb0
    [  243.683944][  T123] [c00000000c38fcb0] [c0000000008240b8] kernfs_fop_write_iter+0x198/0x2d0
    [  243.683951][  T123] [c00000000c38fd00] [c00000000071b9ac] vfs_write+0x34c/0x650
    [  243.683958][  T123] [c00000000c38fdc0] [c00000000071bea8] ksys_write+0x88/0x150
    [  243.683966][  T123] [c00000000c38fe10] [c0000000000317f4] system_call_exception+0x124/0x340
    [  243.683973][  T123] [c00000000c38fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
    ...
    [  243.684087][  T123] Showing all locks held in the system:
    [  243.684095][  T123] 1 lock held by khungtaskd/123:
    [  243.684099][  T123]  #0: c00000000278e370 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x50/0x248
    [  243.684114][  T123] 4 locks held by stress.sh/4365:
    [  243.684119][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684132][  T123]  #1: c000000041aea888 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684143][  T123]  #2: c0000000366fb9a8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684155][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_enable+0x30/0x60
    [  243.684166][  T123] 5 locks held by stress.sh/4366:
    [  243.684170][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684183][  T123]  #1: c00000000aee2288 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684194][  T123]  #2: c0000000366f4ba8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684205][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_disable+0x30/0x60
    [  243.684216][  T123]  #4: c0000003ff9bbf18 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x138/0x12a0

From the ibmveth debug, two threads are calling veth_pool_store, which
calls ibmveth_close and ibmveth_open. Here's the sequence:

  T4365             T4366
  ----------------- ----------------- ---------
  veth_pool_store   veth_pool_store
                    ibmveth_close
  ibmveth_close
  napi_disable
                    napi_disable
  ibmveth_open
  napi_enable                         <- HANG

ibmveth_close calls napi_disable at the top and ibmveth_open calls
napi_enable at the top.

https://docs.kernel.org/networking/napi.html]] says

  The control APIs are not idempotent. Control API calls are safe
  against concurrent use of datapath APIs but an incorrect sequence of
  control API calls may result in crashes, deadlocks, or race
  conditions. For example, calling napi_disable() multiple times in a
  row will deadlock.

In the normal open and close paths, rtnl_mutex is acquired to prevent
other callers. This is missing from veth_pool_store. Use rtnl_mutex in
veth_pool_store fixes these hangs.

Signed-off-by: Dave Marquardt <[email protected]>
Fixes: 860f242 ("[PATCH] ibmveth change buffer pools dynamically")
Reviewed-by: Nick Child <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
Commit 7da55c2 ("drm/amd/display: Remove incorrect FP context
start") removes the FP context protection of dml2_create(), and it said
"All the DC_FP_START/END should be used before call anything from DML2".

However, dml2_validate()/dml21_validate() are not protected from their
callers, causing such errors:

 do_fpu invoked from kernel context![#1]:
 CPU: 10 UID: 0 PID: 331 Comm: kworker/10:1H Not tainted 6.14.0-rc6+ #4
 Workqueue: events_highpri dm_irq_work_func [amdgpu]
 pc ffff800003191eb0 ra ffff800003191e60 tp 9000000107a94000 sp 9000000107a975b0
 a0 9000000140ce4910 a1 0000000000000000 a2 9000000140ce49b0 a3 9000000140ce49a8
 a4 9000000140ce49a8 a5 0000000100000000 a6 0000000000000001 a7 9000000107a97660
 t0 ffff800003790000 t1 9000000140ce5000 t2 0000000000000001 t3 0000000000000000
 t4 0000000000000004 t5 0000000000000000 t6 0000000000000000 t7 0000000000000000
 t8 0000000100000000 u0 ffff8000031a3b9c s9 9000000130bc0000 s0 9000000132400000
 s1 9000000140ec0000 s2 9000000132400000 s3 9000000140ce0000 s4 90000000057f8b88
 s5 9000000140ec0000 s6 9000000140ce4910 s7 0000000000000001 s8 9000000130d45010
 ra: ffff800003191e60 dml21_map_dc_state_into_dml_display_cfg+0x40/0x1140 [amdgpu]
   ERA: ffff800003191eb0 dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  PRMD: 00000004 (PPLV0 +PIE -PWE)
  EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
  ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
 ESTAT: 000f0000 [FPD] (IS= ECode=15 EsubCode=0)
  PRID: 0014d010 (Loongson-64bit, Loongson-3C6000/S)
 Process kworker/10:1H (pid: 331, threadinfo=000000007bf9ddb0, task=00000000cc4ab9f3)
 Stack : 0000000100000000 0000043800000780 0000000100000001 0000000100000001
         0000000000000000 0000078000000000 0000000000000438 0000078000000000
         0000000000000438 0000078000000000 0000000000000438 0000000100000000
         0000000100000000 0000000100000000 0000000100000000 0000000100000000
         0000000000000001 9000000140ec0000 9000000132400000 9000000132400000
         ffff800003408000 ffff800003408000 9000000132400000 9000000140ce0000
         9000000140ce0000 ffff800003193850 0000000000000001 9000000140ec0000
         9000000132400000 9000000140ec0860 9000000140ec0738 0000000000000001
         90000001405e8000 9000000130bc0000 9000000140ec02a8 ffff8000031b5db8
         0000000000000000 0000043800000780 0000000000000003 ffff8000031b79cc
         ...
 Call Trace:
 [<ffff800003191eb0>] dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
 [<ffff80000319384c>] dml21_validate+0xcc/0x520 [amdgpu]
 [<ffff8000031b8948>] dc_validate_global_state+0x2e8/0x460 [amdgpu]
 [<ffff800002e94034>] create_validate_stream_for_sink+0x3d4/0x420 [amdgpu]
 [<ffff800002e940e4>] amdgpu_dm_connector_mode_valid+0x64/0x240 [amdgpu]
 [<900000000441d6b8>] drm_connector_mode_valid+0x38/0x80
 [<900000000441d824>] __drm_helper_update_and_validate+0x124/0x3e0
 [<900000000441ddc0>] drm_helper_probe_single_connector_modes+0x2e0/0x620
 [<90000000044050dc>] drm_client_modeset_probe+0x23c/0x1780
 [<9000000004420384>] __drm_fb_helper_initial_config_and_unlock+0x44/0x5a0
 [<9000000004403acc>] drm_client_dev_hotplug+0xcc/0x140
 [<ffff800002e9ab50>] handle_hpd_irq_helper+0x1b0/0x1e0 [amdgpu]
 [<90000000038f5da0>] process_one_work+0x160/0x300
 [<90000000038f6718>] worker_thread+0x318/0x440
 [<9000000003901b8c>] kthread+0x12c/0x220
 [<90000000038b1484>] ret_from_kernel_thread+0x8/0xa4

Unfortunately, protecting dml2_validate()/dml21_validate() out of DML2
causes "sleeping function called from invalid context", so protect them
with DC_FP_START() and DC_FP_END() inside.

Fixes: 7da55c2 ("drm/amd/display: Remove incorrect FP context start")
Cc: [email protected]
Signed-off-by: Huacai Chen <[email protected]>
Tested-by: Dongyan Qian <[email protected]>
Reviewed-by: Aurabindo Pillai <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
If we finds a vq without a name in our input array in
virtio_ccw_find_vqs(), we treat it as "non-existing" and set the vq pointer
to NULL; we will not call virtio_ccw_setup_vq() to allocate/setup a vq.

Consequently, we create only a queue if it actually exists (name != NULL)
and assign an incremental queue index to each such existing queue.

However, in virtio_ccw_register_adapter_ind()->get_airq_indicator() we
will not ignore these "non-existing queues", but instead assign an airq
indicator to them.

Besides never releasing them in virtio_ccw_drop_indicators() (because
there is no virtqueue), the bigger issue seems to be that there will be a
disagreement between the device and the Linux guest about the airq
indicator to be used for notifying a queue, because the indicator bit
for adapter I/O interrupt is derived from the queue index.

The virtio spec states under "Setting Up Two-Stage Queue Indicators":

	... indicator contains the guest address of an area wherein the
	indicators for the devices are contained, starting at bit_nr, one
	bit per virtqueue of the device.

And further in "Notification via Adapter I/O Interrupts":

	For notifying the driver of virtqueue buffers, the device sets the
	bit in the guest-provided indicator area at the corresponding
	offset.

For example, QEMU uses in virtio_ccw_notify() the queue index (passed as
"vector") to select the relevant indicator bit. If a queue does not exist,
it does not have a corresponding indicator bit assigned, because it
effectively doesn't have a queue index.

Using a virtio-balloon-ccw device under QEMU with free-page-hinting
disabled ("free-page-hint=off") but free-page-reporting enabled
("free-page-reporting=on") will result in free page reporting
not working as expected: in the virtio_balloon driver, we'll be stuck
forever in virtballoon_free_page_report()->wait_event(), because the
waitqueue will not be woken up as the notification from the device is
lost: it would use the wrong indicator bit.

Free page reporting stops working and we get splats (when configured to
detect hung wqs) like:

 INFO: task kworker/1:3:463 blocked for more than 61 seconds.
       Not tainted 6.14.0 #4
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:kworker/1:3 [...]
 Workqueue: events page_reporting_process
 Call Trace:
  [<000002f404e6dfb2>] __schedule+0x402/0x1640
  [<000002f404e6f22e>] schedule+0x3e/0xe0
  [<000002f3846a88fa>] virtballoon_free_page_report+0xaa/0x110 [virtio_balloon]
  [<000002f40435c8a4>] page_reporting_process+0x2e4/0x740
  [<000002f403fd3ee2>] process_one_work+0x1c2/0x400
  [<000002f403fd4b96>] worker_thread+0x296/0x420
  [<000002f403fe10b4>] kthread+0x124/0x290
  [<000002f403f4e0dc>] __ret_from_fork+0x3c/0x60
  [<000002f404e77272>] ret_from_fork+0xa/0x38

There was recently a discussion [1] whether the "holes" should be
treated differently again, effectively assigning also non-existing
queues a queue index: that should also fix the issue, but requires other
workarounds to not break existing setups.

Let's fix it without affecting existing setups for now by properly ignoring
the non-existing queues, so the indicator bits will match the queue
indexes.

[1] https://lore.kernel.org/all/[email protected]/

Fixes: a229989 ("virtio: don't allocate vqs when names[i] = NULL")
Reported-by: Chandra Merla <[email protected]>
Cc: [email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Tested-by: Thomas Huth <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
…ate_pagetables'

[ Upstream commit fddc450 ]

This commit addresses a circular locking dependency in the
svm_range_cpu_invalidate_pagetables function. The function previously
held a lock while determining whether to perform an unmap or eviction
operation, which could lead to deadlocks.

Fixes the below:

[  223.418794] ======================================================
[  223.418820] WARNING: possible circular locking dependency detected
[  223.418845] 6.12.0-amdstaging-drm-next-lol-050225 #14 Tainted: G     U     OE
[  223.418869] ------------------------------------------------------
[  223.418889] kfdtest/3939 is trying to acquire lock:
[  223.418906] ffff8957552eae38 (&dqm->lock_hidden){+.+.}-{3:3}, at: evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.419302]
               but task is already holding lock:
[  223.419303] ffff8957556b83b0 (&prange->lock){+.+.}-{3:3}, at: svm_range_cpu_invalidate_pagetables+0x9d/0x850 [amdgpu]
[  223.419447] Console: switching to colour dummy device 80x25
[  223.419477] [IGT] amd_basic: executing
[  223.419599]
               which lock already depends on the new lock.

[  223.419611]
               the existing dependency chain (in reverse order) is:
[  223.419621]
               -> #2 (&prange->lock){+.+.}-{3:3}:
[  223.419636]        __mutex_lock+0x85/0xe20
[  223.419647]        mutex_lock_nested+0x1b/0x30
[  223.419656]        svm_range_validate_and_map+0x2f1/0x15b0 [amdgpu]
[  223.419954]        svm_range_set_attr+0xe8c/0x1710 [amdgpu]
[  223.420236]        svm_ioctl+0x46/0x50 [amdgpu]
[  223.420503]        kfd_ioctl_svm+0x50/0x90 [amdgpu]
[  223.420763]        kfd_ioctl+0x409/0x6d0 [amdgpu]
[  223.421024]        __x64_sys_ioctl+0x95/0xd0
[  223.421036]        x64_sys_call+0x1205/0x20d0
[  223.421047]        do_syscall_64+0x87/0x140
[  223.421056]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.421068]
               -> #1 (reservation_ww_class_mutex){+.+.}-{3:3}:
[  223.421084]        __ww_mutex_lock.constprop.0+0xab/0x1560
[  223.421095]        ww_mutex_lock+0x2b/0x90
[  223.421103]        amdgpu_amdkfd_alloc_gtt_mem+0xcc/0x2b0 [amdgpu]
[  223.421361]        add_queue_mes+0x3bc/0x440 [amdgpu]
[  223.421623]        unhalt_cpsch+0x1ae/0x240 [amdgpu]
[  223.421888]        kgd2kfd_start_sched+0x5e/0xd0 [amdgpu]
[  223.422148]        amdgpu_amdkfd_start_sched+0x3d/0x50 [amdgpu]
[  223.422414]        amdgpu_gfx_enforce_isolation_handler+0x132/0x270 [amdgpu]
[  223.422662]        process_one_work+0x21e/0x680
[  223.422673]        worker_thread+0x190/0x330
[  223.422682]        kthread+0xe7/0x120
[  223.422690]        ret_from_fork+0x3c/0x60
[  223.422699]        ret_from_fork_asm+0x1a/0x30
[  223.422708]
               -> #0 (&dqm->lock_hidden){+.+.}-{3:3}:
[  223.422723]        __lock_acquire+0x16f4/0x2810
[  223.422734]        lock_acquire+0xd1/0x300
[  223.422742]        __mutex_lock+0x85/0xe20
[  223.422751]        mutex_lock_nested+0x1b/0x30
[  223.422760]        evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.423025]        kfd_process_evict_queues+0x8a/0x1d0 [amdgpu]
[  223.423285]        kgd2kfd_quiesce_mm+0x43/0x90 [amdgpu]
[  223.423540]        svm_range_cpu_invalidate_pagetables+0x4a7/0x850 [amdgpu]
[  223.423807]        __mmu_notifier_invalidate_range_start+0x1f5/0x250
[  223.423819]        copy_page_range+0x1e94/0x1ea0
[  223.423829]        copy_process+0x172f/0x2ad0
[  223.423839]        kernel_clone+0x9c/0x3f0
[  223.423847]        __do_sys_clone+0x66/0x90
[  223.423856]        __x64_sys_clone+0x25/0x30
[  223.423864]        x64_sys_call+0x1d7c/0x20d0
[  223.423872]        do_syscall_64+0x87/0x140
[  223.423880]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.423891]
               other info that might help us debug this:

[  223.423903] Chain exists of:
                 &dqm->lock_hidden --> reservation_ww_class_mutex --> &prange->lock

[  223.423926]  Possible unsafe locking scenario:

[  223.423935]        CPU0                    CPU1
[  223.423942]        ----                    ----
[  223.423949]   lock(&prange->lock);
[  223.423958]                                lock(reservation_ww_class_mutex);
[  223.423970]                                lock(&prange->lock);
[  223.423981]   lock(&dqm->lock_hidden);
[  223.423990]
                *** DEADLOCK ***

[  223.423999] 5 locks held by kfdtest/3939:
[  223.424006]  #0: ffffffffb82b4fc0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x1387/0x2ad0
[  223.424026]  #1: ffff89575eda81b0 (&mm->mmap_lock){++++}-{3:3}, at: copy_process+0x13a8/0x2ad0
[  223.424046]  #2: ffff89575edaf3b0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_process+0x13e4/0x2ad0
[  223.424066]  #3: ffffffffb82e76e0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: copy_page_range+0x1cea/0x1ea0
[  223.424088]  #4: ffff8957556b83b0 (&prange->lock){+.+.}-{3:3}, at: svm_range_cpu_invalidate_pagetables+0x9d/0x850 [amdgpu]
[  223.424365]
               stack backtrace:
[  223.424374] CPU: 0 UID: 0 PID: 3939 Comm: kfdtest Tainted: G     U     OE      6.12.0-amdstaging-drm-next-lol-050225 #14
[  223.424392] Tainted: [U]=USER, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
[  223.424401] Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS PRO WIFI/X570 AORUS PRO WIFI, BIOS F36a 02/16/2022
[  223.424416] Call Trace:
[  223.424423]  <TASK>
[  223.424430]  dump_stack_lvl+0x9b/0xf0
[  223.424441]  dump_stack+0x10/0x20
[  223.424449]  print_circular_bug+0x275/0x350
[  223.424460]  check_noncircular+0x157/0x170
[  223.424469]  ? __bfs+0xfd/0x2c0
[  223.424481]  __lock_acquire+0x16f4/0x2810
[  223.424490]  ? srso_return_thunk+0x5/0x5f
[  223.424505]  lock_acquire+0xd1/0x300
[  223.424514]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.424783]  __mutex_lock+0x85/0xe20
[  223.424792]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425058]  ? srso_return_thunk+0x5/0x5f
[  223.425067]  ? mark_held_locks+0x54/0x90
[  223.425076]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425339]  ? srso_return_thunk+0x5/0x5f
[  223.425350]  mutex_lock_nested+0x1b/0x30
[  223.425358]  ? mutex_lock_nested+0x1b/0x30
[  223.425367]  evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425631]  kfd_process_evict_queues+0x8a/0x1d0 [amdgpu]
[  223.425893]  kgd2kfd_quiesce_mm+0x43/0x90 [amdgpu]
[  223.426156]  svm_range_cpu_invalidate_pagetables+0x4a7/0x850 [amdgpu]
[  223.426423]  ? srso_return_thunk+0x5/0x5f
[  223.426436]  __mmu_notifier_invalidate_range_start+0x1f5/0x250
[  223.426450]  copy_page_range+0x1e94/0x1ea0
[  223.426461]  ? srso_return_thunk+0x5/0x5f
[  223.426474]  ? srso_return_thunk+0x5/0x5f
[  223.426484]  ? lock_acquire+0xd1/0x300
[  223.426494]  ? copy_process+0x1718/0x2ad0
[  223.426502]  ? srso_return_thunk+0x5/0x5f
[  223.426510]  ? sched_clock_noinstr+0x9/0x10
[  223.426519]  ? local_clock_noinstr+0xe/0xc0
[  223.426528]  ? copy_process+0x1718/0x2ad0
[  223.426537]  ? srso_return_thunk+0x5/0x5f
[  223.426550]  copy_process+0x172f/0x2ad0
[  223.426569]  kernel_clone+0x9c/0x3f0
[  223.426577]  ? __schedule+0x4c9/0x1b00
[  223.426586]  ? srso_return_thunk+0x5/0x5f
[  223.426594]  ? sched_clock_noinstr+0x9/0x10
[  223.426602]  ? srso_return_thunk+0x5/0x5f
[  223.426610]  ? local_clock_noinstr+0xe/0xc0
[  223.426619]  ? schedule+0x107/0x1a0
[  223.426629]  __do_sys_clone+0x66/0x90
[  223.426643]  __x64_sys_clone+0x25/0x30
[  223.426652]  x64_sys_call+0x1d7c/0x20d0
[  223.426661]  do_syscall_64+0x87/0x140
[  223.426671]  ? srso_return_thunk+0x5/0x5f
[  223.426679]  ? common_nsleep+0x44/0x50
[  223.426690]  ? srso_return_thunk+0x5/0x5f
[  223.426698]  ? trace_hardirqs_off+0x52/0xd0
[  223.426709]  ? srso_return_thunk+0x5/0x5f
[  223.426717]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426727]  ? srso_return_thunk+0x5/0x5f
[  223.426736]  ? do_syscall_64+0x93/0x140
[  223.426748]  ? srso_return_thunk+0x5/0x5f
[  223.426756]  ? up_write+0x1c/0x1e0
[  223.426765]  ? srso_return_thunk+0x5/0x5f
[  223.426775]  ? srso_return_thunk+0x5/0x5f
[  223.426783]  ? trace_hardirqs_off+0x52/0xd0
[  223.426792]  ? srso_return_thunk+0x5/0x5f
[  223.426800]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426810]  ? srso_return_thunk+0x5/0x5f
[  223.426818]  ? do_syscall_64+0x93/0x140
[  223.426826]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426836]  ? srso_return_thunk+0x5/0x5f
[  223.426844]  ? do_syscall_64+0x93/0x140
[  223.426853]  ? srso_return_thunk+0x5/0x5f
[  223.426861]  ? irqentry_exit+0x6b/0x90
[  223.426869]  ? srso_return_thunk+0x5/0x5f
[  223.426877]  ? exc_page_fault+0xa7/0x2c0
[  223.426888]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.426898] RIP: 0033:0x7f46758eab57
[  223.426906] Code: ba 04 00 f3 0f 1e fa 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 41 89 c0 85 c0 75 2c 64 48 8b 04 25 10 00
[  223.426930] RSP: 002b:00007fff5c3e5188 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
[  223.426943] RAX: ffffffffffffffda RBX: 00007f4675f8c040 RCX: 00007f46758eab57
[  223.426954] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
[  223.426965] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  223.426975] R10: 00007f4675e81a50 R11: 0000000000000246 R12: 0000000000000001
[  223.426986] R13: 00007fff5c3e5470 R14: 00007fff5c3e53e0 R15: 00007fff5c3e5410
[  223.427004]  </TASK>

v2: To resolve this issue, the allocation of the process context buffer
(`proc_ctx_bo`) has been moved from the `add_queue_mes` function to the
`pqm_create_queue` function. This change ensures that the buffer is
allocated only when the first queue for a process is created and only if
the Micro Engine Scheduler (MES) is enabled. (Felix)

v3: Fix typo s/Memory Execution Scheduler (MES)/Micro Engine Scheduler
in commit message. (Lijo)

Fixes: 438b39a ("drm/amdkfd: pause autosuspend when creating pdd")
Cc: Jesse Zhang <[email protected]>
Cc: Yunxiang Li <[email protected]>
Cc: Philip Yang <[email protected]>
Cc: Alex Sierra <[email protected]>
Cc: Felix Kuehling <[email protected]>
Cc: Christian König <[email protected]>
Cc: Alex Deucher <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
[ Upstream commit 888751e ]

perf test 11 hwmon fails on s390 with this error

 # ./perf test -Fv 11
 --- start ---
 ---- end ----
 11.1: Basic parsing test             : Ok
 --- start ---
 Testing 'temp_test_hwmon_event1'
 Using CPUID IBM,3931,704,A01,3.7,002f
 temp_test_hwmon_event1 -> hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'temp_test_hwmon_event1', 292470092988416 != 655361
 ---- end ----
 11.2: Parsing without PMU name       : FAILED!
 --- start ---
 Testing 'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/'
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/',
    292470092988416 != 655361
 ---- end ----
 11.3: Parsing with PMU name          : FAILED!
 #

The root cause is in member test_event::config which is initialized
to 0xA0001 or 655361. During event parsing a long list event parsing
functions are called and end up with this gdb call stack:

 #0  hwmon_pmu__config_term (hwm=0x168dfd0, attr=0x3ffffff5ee8,
	term=0x168db60, err=0x3ffffff81c8) at util/hwmon_pmu.c:623
 #1  hwmon_pmu__config_terms (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	terms=0x3ffffff5ea8, err=0x3ffffff81c8) at util/hwmon_pmu.c:662
 #2  0x00000000012f870c in perf_pmu__config_terms (pmu=0x168dfd0,
	attr=0x3ffffff5ee8, terms=0x3ffffff5ea8, zero=false,
	apply_hardcoded=false, err=0x3ffffff81c8) at util/pmu.c:1519
 #3  0x00000000012f88a4 in perf_pmu__config (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	head_terms=0x3ffffff5ea8, apply_hardcoded=false, err=0x3ffffff81c8)
	at util/pmu.c:1545
 #4  0x00000000012680c4 in parse_events_add_pmu (parse_state=0x3ffffff7fb8,
	list=0x168dc00, pmu=0x168dfd0, const_parsed_terms=0x3ffffff6090,
	auto_merge_stats=true, alternate_hw_config=10)
	at util/parse-events.c:1508
 #5  0x00000000012684c6 in parse_events_multi_pmu_add (parse_state=0x3ffffff7fb8,
	event_name=0x168ec10 "temp_test_hwmon_event1", hw_config=10,
	const_parsed_terms=0x0, listp=0x3ffffff6230, loc_=0x3ffffff70e0)
	at util/parse-events.c:1592
 #6  0x00000000012f0e4e in parse_events_parse (_parse_state=0x3ffffff7fb8,
	scanner=0x16878c0) at util/parse-events.y:293
 #7  0x00000000012695a0 in parse_events__scanner (str=0x3ffffff81d8
	"temp_test_hwmon_event1", input=0x0, parse_state=0x3ffffff7fb8)
	at util/parse-events.c:1867
 #8  0x000000000126a1e8 in __parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", pmu_filter=0x0,
	err=0x3ffffff81c8, fake_pmu=false, warn_if_reordered=true,
	fake_tp=false) at util/parse-events.c:2136
 #9  0x00000000011e36aa in parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", err=0x3ffffff81c8)
	at /root/linux/tools/perf/util/parse-events.h:41
 #10 0x00000000011e3e64 in do_test (i=0, with_pmu=false, with_alias=false)
	at tests/hwmon_pmu.c:164
 #11 0x00000000011e422c in test__hwmon_pmu (with_pmu=false)
	at tests/hwmon_pmu.c:219
 #12 0x00000000011e431c in test__hwmon_pmu_without_pmu (test=0x1610368
	<suite.hwmon_pmu>, subtest=1) at tests/hwmon_pmu.c:23

where the attr::config is set to value 292470092988416 or 0x10a0000000000
in line 625 of file ./util/hwmon_pmu.c:

   attr->config = key.type_and_num;

However member key::type_and_num is defined as union and bit field:

   union hwmon_pmu_event_key {
        long type_and_num;
        struct {
                int num :16;
                enum hwmon_type type :8;
        };
   };

s390 is big endian and Intel is little endian architecture.
The events for the hwmon dummy pmu have num = 1 or num = 2 and
type is set to HWMON_TYPE_TEMP (which is 10).
On s390 this assignes member key::type_and_num the value of
0x10a0000000000 (which is 292470092988416) as shown in above
trace output.

Fix this and export the structure/union hwmon_pmu_event_key
so the test shares the same implementation as the event parsing
functions for union and bit fields. This should avoid
endianess issues on all platforms.

Output after:
 # ./perf test -F 11
 11.1: Basic parsing test         : Ok
 11.2: Parsing without PMU name   : Ok
 11.3: Parsing with PMU name      : Ok
 #

Fixes: 531ee0f ("perf test: Add hwmon "PMU" test")
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
…cal section

[ Upstream commit 85b2b9c ]

A circular lock dependency splat has been seen involving down_trylock():

  ======================================================
  WARNING: possible circular locking dependency detected
  6.12.0-41.el10.s390x+debug
  ------------------------------------------------------
  dd/32479 is trying to acquire lock:
  0015a20accd0d4f8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x26/0x90

  but task is already holding lock:
  000000017e461698 (&zone->lock){-.-.}-{2:2}, at: rmqueue_bulk+0xac/0x8f0

  the existing dependency chain (in reverse order) is:
  -> #4 (&zone->lock){-.-.}-{2:2}:
  -> #3 (hrtimer_bases.lock){-.-.}-{2:2}:
  -> #2 (&rq->__lock){-.-.}-{2:2}:
  -> #1 (&p->pi_lock){-.-.}-{2:2}:
  -> #0 ((console_sem).lock){-.-.}-{2:2}:

The console_sem -> pi_lock dependency is due to calling try_to_wake_up()
while holding the console_sem raw_spinlock. This dependency can be broken
by using wake_q to do the wakeup instead of calling try_to_wake_up()
under the console_sem lock. This will also make the semaphore's
raw_spinlock become a terminal lock without taking any further locks
underneath it.

The hrtimer_bases.lock is a raw_spinlock while zone->lock is a
spinlock. The hrtimer_bases.lock -> zone->lock dependency happens via
the debug_objects_fill_pool() helper function in the debugobjects code.

  -> #4 (&zone->lock){-.-.}-{2:2}:
         __lock_acquire+0xe86/0x1cc0
         lock_acquire.part.0+0x258/0x630
         lock_acquire+0xb8/0xe0
         _raw_spin_lock_irqsave+0xb4/0x120
         rmqueue_bulk+0xac/0x8f0
         __rmqueue_pcplist+0x580/0x830
         rmqueue_pcplist+0xfc/0x470
         rmqueue.isra.0+0xdec/0x11b0
         get_page_from_freelist+0x2ee/0xeb0
         __alloc_pages_noprof+0x2c2/0x520
         alloc_pages_mpol_noprof+0x1fc/0x4d0
         alloc_pages_noprof+0x8c/0xe0
         allocate_slab+0x320/0x460
         ___slab_alloc+0xa58/0x12b0
         __slab_alloc.isra.0+0x42/0x60
         kmem_cache_alloc_noprof+0x304/0x350
         fill_pool+0xf6/0x450
         debug_object_activate+0xfe/0x360
         enqueue_hrtimer+0x34/0x190
         __run_hrtimer+0x3c8/0x4c0
         __hrtimer_run_queues+0x1b2/0x260
         hrtimer_interrupt+0x316/0x760
         do_IRQ+0x9a/0xe0
         do_irq_async+0xf6/0x160

Normally a raw_spinlock to spinlock dependency is not legitimate
and will be warned if CONFIG_PROVE_RAW_LOCK_NESTING is enabled,
but debug_objects_fill_pool() is an exception as it explicitly
allows this dependency for non-PREEMPT_RT kernel without causing
PROVE_RAW_LOCK_NESTING lockdep splat. As a result, this dependency is
legitimate and not a bug.

Anyway, semaphore is the only locking primitive left that is still
using try_to_wake_up() to do wakeup inside critical section, all the
other locking primitives had been migrated to use wake_q to do wakeup
outside of the critical section. It is also possible that there are
other circular locking dependencies involving printk/console_sem or
other existing/new semaphores lurking somewhere which may show up in
the future. Let just do the migration now to wake_q to avoid headache
like this.

Reported-by: [email protected]
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
[ Upstream commit 053f3ff ]

v2:
- Created a single error handling unlock and exit in veth_pool_store
- Greatly expanded commit message with previous explanatory-only text

Summary: Use rtnl_mutex to synchronize veth_pool_store with itself,
ibmveth_close and ibmveth_open, preventing multiple calls in a row to
napi_disable.

Background: Two (or more) threads could call veth_pool_store through
writing to /sys/devices/vio/30000002/pool*/*. You can do this easily
with a little shell script. This causes a hang.

I configured LOCKDEP, compiled ibmveth.c with DEBUG, and built a new
kernel. I ran this test again and saw:

    Setting pool0/active to 0
    Setting pool1/active to 1
    [   73.911067][ T4365] ibmveth 30000002 eth0: close starting
    Setting pool1/active to 1
    Setting pool1/active to 0
    [   73.911367][ T4366] ibmveth 30000002 eth0: close starting
    [   73.916056][ T4365] ibmveth 30000002 eth0: close complete
    [   73.916064][ T4365] ibmveth 30000002 eth0: open starting
    [  110.808564][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  230.808495][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  243.683786][  T123] INFO: task stress.sh:4365 blocked for more than 122 seconds.
    [  243.683827][  T123]       Not tainted 6.14.0-01103-g2df0c02dab82-dirty #8
    [  243.683833][  T123] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    [  243.683838][  T123] task:stress.sh       state:D stack:28096 pid:4365  tgid:4365  ppid:4364   task_flags:0x400040 flags:0x00042000
    [  243.683852][  T123] Call Trace:
    [  243.683857][  T123] [c00000000c38f690] [0000000000000001] 0x1 (unreliable)
    [  243.683868][  T123] [c00000000c38f840] [c00000000001f908] __switch_to+0x318/0x4e0
    [  243.683878][  T123] [c00000000c38f8a0] [c000000001549a70] __schedule+0x500/0x12a0
    [  243.683888][  T123] [c00000000c38f9a0] [c00000000154a878] schedule+0x68/0x210
    [  243.683896][  T123] [c00000000c38f9d0] [c00000000154ac80] schedule_preempt_disabled+0x30/0x50
    [  243.683904][  T123] [c00000000c38fa00] [c00000000154dbb0] __mutex_lock+0x730/0x10f0
    [  243.683913][  T123] [c00000000c38fb10] [c000000001154d40] napi_enable+0x30/0x60
    [  243.683921][  T123] [c00000000c38fb40] [c000000000f4ae94] ibmveth_open+0x68/0x5dc
    [  243.683928][  T123] [c00000000c38fbe0] [c000000000f4aa20] veth_pool_store+0x220/0x270
    [  243.683936][  T123] [c00000000c38fc70] [c000000000826278] sysfs_kf_write+0x68/0xb0
    [  243.683944][  T123] [c00000000c38fcb0] [c0000000008240b8] kernfs_fop_write_iter+0x198/0x2d0
    [  243.683951][  T123] [c00000000c38fd00] [c00000000071b9ac] vfs_write+0x34c/0x650
    [  243.683958][  T123] [c00000000c38fdc0] [c00000000071bea8] ksys_write+0x88/0x150
    [  243.683966][  T123] [c00000000c38fe10] [c0000000000317f4] system_call_exception+0x124/0x340
    [  243.683973][  T123] [c00000000c38fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
    ...
    [  243.684087][  T123] Showing all locks held in the system:
    [  243.684095][  T123] 1 lock held by khungtaskd/123:
    [  243.684099][  T123]  #0: c00000000278e370 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x50/0x248
    [  243.684114][  T123] 4 locks held by stress.sh/4365:
    [  243.684119][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684132][  T123]  #1: c000000041aea888 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684143][  T123]  #2: c0000000366fb9a8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684155][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_enable+0x30/0x60
    [  243.684166][  T123] 5 locks held by stress.sh/4366:
    [  243.684170][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684183][  T123]  #1: c00000000aee2288 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684194][  T123]  #2: c0000000366f4ba8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684205][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_disable+0x30/0x60
    [  243.684216][  T123]  #4: c0000003ff9bbf18 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x138/0x12a0

From the ibmveth debug, two threads are calling veth_pool_store, which
calls ibmveth_close and ibmveth_open. Here's the sequence:

  T4365             T4366
  ----------------- ----------------- ---------
  veth_pool_store   veth_pool_store
                    ibmveth_close
  ibmveth_close
  napi_disable
                    napi_disable
  ibmveth_open
  napi_enable                         <- HANG

ibmveth_close calls napi_disable at the top and ibmveth_open calls
napi_enable at the top.

https://docs.kernel.org/networking/napi.html]] says

  The control APIs are not idempotent. Control API calls are safe
  against concurrent use of datapath APIs but an incorrect sequence of
  control API calls may result in crashes, deadlocks, or race
  conditions. For example, calling napi_disable() multiple times in a
  row will deadlock.

In the normal open and close paths, rtnl_mutex is acquired to prevent
other callers. This is missing from veth_pool_store. Use rtnl_mutex in
veth_pool_store fixes these hangs.

Signed-off-by: Dave Marquardt <[email protected]>
Fixes: 860f242 ("[PATCH] ibmveth change buffer pools dynamically")
Reviewed-by: Nick Child <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
[ Upstream commit b61e69b ]

syzbot report a deadlock in diFree. [1]

When calling "ioctl$LOOP_SET_STATUS64", the offset value passed in is 4,
which does not match the mounted loop device, causing the mapping of the
mounted loop device to be invalidated.

When creating the directory and creating the inode of iag in diReadSpecial(),
read the page of fixed disk inode (AIT) in raw mode in read_metapage(), the
metapage data it returns is corrupted, which causes the nlink value of 0 to be
assigned to the iag inode when executing copy_from_dinode(), which ultimately
causes a deadlock when entering diFree().

To avoid this, first check the nlink value of dinode before setting iag inode.

[1]
WARNING: possible recursive locking detected
6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0 Not tainted
--------------------------------------------
syz-executor301/5309 is trying to acquire lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889

but task is already holding lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(imap->im_aglock[index]));
  lock(&(imap->im_aglock[index]));

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor301/5309:
 #0: ffff8880422a4420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:850 [inline]
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x260/0x540 fs/namei.c:4026
 #2: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2460 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocAG+0x4b7/0x1e50 fs/jfs/jfs_imap.c:1669
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2477 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocAG+0x869/0x1e50 fs/jfs/jfs_imap.c:1669

stack backtrace:
CPU: 0 UID: 0 PID: 5309 Comm: syz-executor301 Not tainted 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889
 jfs_evict_inode+0x32d/0x440 fs/jfs/inode.c:156
 evict+0x4e8/0x9b0 fs/inode.c:725
 diFreeSpecial fs/jfs/jfs_imap.c:552 [inline]
 duplicateIXtree+0x3c6/0x550 fs/jfs/jfs_imap.c:3022
 diNewIAG fs/jfs/jfs_imap.c:2597 [inline]
 diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 diAllocAG+0x17dc/0x1e50 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d2/0x1630 fs/jfs/jfs_imap.c:1590
 ialloc+0x8f/0x900 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x1c5/0xba0 fs/jfs/namei.c:225
 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
 do_mkdirat+0x264/0x3a0 fs/namei.c:4280
 __do_sys_mkdirat fs/namei.c:4295 [inline]
 __se_sys_mkdirat fs/namei.c:4293 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=355da3b3a74881008e8f
Signed-off-by: Edward Adam Davis <[email protected]>
Signed-off-by: Dave Kleikamp <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 2ccd42b upstream.

If we finds a vq without a name in our input array in
virtio_ccw_find_vqs(), we treat it as "non-existing" and set the vq pointer
to NULL; we will not call virtio_ccw_setup_vq() to allocate/setup a vq.

Consequently, we create only a queue if it actually exists (name != NULL)
and assign an incremental queue index to each such existing queue.

However, in virtio_ccw_register_adapter_ind()->get_airq_indicator() we
will not ignore these "non-existing queues", but instead assign an airq
indicator to them.

Besides never releasing them in virtio_ccw_drop_indicators() (because
there is no virtqueue), the bigger issue seems to be that there will be a
disagreement between the device and the Linux guest about the airq
indicator to be used for notifying a queue, because the indicator bit
for adapter I/O interrupt is derived from the queue index.

The virtio spec states under "Setting Up Two-Stage Queue Indicators":

	... indicator contains the guest address of an area wherein the
	indicators for the devices are contained, starting at bit_nr, one
	bit per virtqueue of the device.

And further in "Notification via Adapter I/O Interrupts":

	For notifying the driver of virtqueue buffers, the device sets the
	bit in the guest-provided indicator area at the corresponding
	offset.

For example, QEMU uses in virtio_ccw_notify() the queue index (passed as
"vector") to select the relevant indicator bit. If a queue does not exist,
it does not have a corresponding indicator bit assigned, because it
effectively doesn't have a queue index.

Using a virtio-balloon-ccw device under QEMU with free-page-hinting
disabled ("free-page-hint=off") but free-page-reporting enabled
("free-page-reporting=on") will result in free page reporting
not working as expected: in the virtio_balloon driver, we'll be stuck
forever in virtballoon_free_page_report()->wait_event(), because the
waitqueue will not be woken up as the notification from the device is
lost: it would use the wrong indicator bit.

Free page reporting stops working and we get splats (when configured to
detect hung wqs) like:

 INFO: task kworker/1:3:463 blocked for more than 61 seconds.
       Not tainted 6.14.0 #4
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:kworker/1:3 [...]
 Workqueue: events page_reporting_process
 Call Trace:
  [<000002f404e6dfb2>] __schedule+0x402/0x1640
  [<000002f404e6f22e>] schedule+0x3e/0xe0
  [<000002f3846a88fa>] virtballoon_free_page_report+0xaa/0x110 [virtio_balloon]
  [<000002f40435c8a4>] page_reporting_process+0x2e4/0x740
  [<000002f403fd3ee2>] process_one_work+0x1c2/0x400
  [<000002f403fd4b96>] worker_thread+0x296/0x420
  [<000002f403fe10b4>] kthread+0x124/0x290
  [<000002f403f4e0dc>] __ret_from_fork+0x3c/0x60
  [<000002f404e77272>] ret_from_fork+0xa/0x38

There was recently a discussion [1] whether the "holes" should be
treated differently again, effectively assigning also non-existing
queues a queue index: that should also fix the issue, but requires other
workarounds to not break existing setups.

Let's fix it without affecting existing setups for now by properly ignoring
the non-existing queues, so the indicator bits will match the queue
indexes.

[1] https://lore.kernel.org/all/[email protected]/

Fixes: a229989 ("virtio: don't allocate vqs when names[i] = NULL")
Reported-by: Chandra Merla <[email protected]>
Cc: [email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Tested-by: Thomas Huth <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
[ Upstream commit b61e69b ]

syzbot report a deadlock in diFree. [1]

When calling "ioctl$LOOP_SET_STATUS64", the offset value passed in is 4,
which does not match the mounted loop device, causing the mapping of the
mounted loop device to be invalidated.

When creating the directory and creating the inode of iag in diReadSpecial(),
read the page of fixed disk inode (AIT) in raw mode in read_metapage(), the
metapage data it returns is corrupted, which causes the nlink value of 0 to be
assigned to the iag inode when executing copy_from_dinode(), which ultimately
causes a deadlock when entering diFree().

To avoid this, first check the nlink value of dinode before setting iag inode.

[1]
WARNING: possible recursive locking detected
6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0 Not tainted
--------------------------------------------
syz-executor301/5309 is trying to acquire lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889

but task is already holding lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(imap->im_aglock[index]));
  lock(&(imap->im_aglock[index]));

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor301/5309:
 #0: ffff8880422a4420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:850 [inline]
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x260/0x540 fs/namei.c:4026
 #2: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2460 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocAG+0x4b7/0x1e50 fs/jfs/jfs_imap.c:1669
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2477 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocAG+0x869/0x1e50 fs/jfs/jfs_imap.c:1669

stack backtrace:
CPU: 0 UID: 0 PID: 5309 Comm: syz-executor301 Not tainted 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889
 jfs_evict_inode+0x32d/0x440 fs/jfs/inode.c:156
 evict+0x4e8/0x9b0 fs/inode.c:725
 diFreeSpecial fs/jfs/jfs_imap.c:552 [inline]
 duplicateIXtree+0x3c6/0x550 fs/jfs/jfs_imap.c:3022
 diNewIAG fs/jfs/jfs_imap.c:2597 [inline]
 diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 diAllocAG+0x17dc/0x1e50 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d2/0x1630 fs/jfs/jfs_imap.c:1590
 ialloc+0x8f/0x900 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x1c5/0xba0 fs/jfs/namei.c:225
 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
 do_mkdirat+0x264/0x3a0 fs/namei.c:4280
 __do_sys_mkdirat fs/namei.c:4295 [inline]
 __se_sys_mkdirat fs/namei.c:4293 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=355da3b3a74881008e8f
Signed-off-by: Edward Adam Davis <[email protected]>
Signed-off-by: Dave Kleikamp <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 2ccd42b upstream.

If we finds a vq without a name in our input array in
virtio_ccw_find_vqs(), we treat it as "non-existing" and set the vq pointer
to NULL; we will not call virtio_ccw_setup_vq() to allocate/setup a vq.

Consequently, we create only a queue if it actually exists (name != NULL)
and assign an incremental queue index to each such existing queue.

However, in virtio_ccw_register_adapter_ind()->get_airq_indicator() we
will not ignore these "non-existing queues", but instead assign an airq
indicator to them.

Besides never releasing them in virtio_ccw_drop_indicators() (because
there is no virtqueue), the bigger issue seems to be that there will be a
disagreement between the device and the Linux guest about the airq
indicator to be used for notifying a queue, because the indicator bit
for adapter I/O interrupt is derived from the queue index.

The virtio spec states under "Setting Up Two-Stage Queue Indicators":

	... indicator contains the guest address of an area wherein the
	indicators for the devices are contained, starting at bit_nr, one
	bit per virtqueue of the device.

And further in "Notification via Adapter I/O Interrupts":

	For notifying the driver of virtqueue buffers, the device sets the
	bit in the guest-provided indicator area at the corresponding
	offset.

For example, QEMU uses in virtio_ccw_notify() the queue index (passed as
"vector") to select the relevant indicator bit. If a queue does not exist,
it does not have a corresponding indicator bit assigned, because it
effectively doesn't have a queue index.

Using a virtio-balloon-ccw device under QEMU with free-page-hinting
disabled ("free-page-hint=off") but free-page-reporting enabled
("free-page-reporting=on") will result in free page reporting
not working as expected: in the virtio_balloon driver, we'll be stuck
forever in virtballoon_free_page_report()->wait_event(), because the
waitqueue will not be woken up as the notification from the device is
lost: it would use the wrong indicator bit.

Free page reporting stops working and we get splats (when configured to
detect hung wqs) like:

 INFO: task kworker/1:3:463 blocked for more than 61 seconds.
       Not tainted 6.14.0 #4
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:kworker/1:3 [...]
 Workqueue: events page_reporting_process
 Call Trace:
  [<000002f404e6dfb2>] __schedule+0x402/0x1640
  [<000002f404e6f22e>] schedule+0x3e/0xe0
  [<000002f3846a88fa>] virtballoon_free_page_report+0xaa/0x110 [virtio_balloon]
  [<000002f40435c8a4>] page_reporting_process+0x2e4/0x740
  [<000002f403fd3ee2>] process_one_work+0x1c2/0x400
  [<000002f403fd4b96>] worker_thread+0x296/0x420
  [<000002f403fe10b4>] kthread+0x124/0x290
  [<000002f403f4e0dc>] __ret_from_fork+0x3c/0x60
  [<000002f404e77272>] ret_from_fork+0xa/0x38

There was recently a discussion [1] whether the "holes" should be
treated differently again, effectively assigning also non-existing
queues a queue index: that should also fix the issue, but requires other
workarounds to not break existing setups.

Let's fix it without affecting existing setups for now by properly ignoring
the non-existing queues, so the indicator bits will match the queue
indexes.

[1] https://lore.kernel.org/all/[email protected]/

Fixes: a229989 ("virtio: don't allocate vqs when names[i] = NULL")
Reported-by: Chandra Merla <[email protected]>
Cc: [email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Tested-by: Thomas Huth <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
…ate_pagetables'

[ Upstream commit fddc450 ]

This commit addresses a circular locking dependency in the
svm_range_cpu_invalidate_pagetables function. The function previously
held a lock while determining whether to perform an unmap or eviction
operation, which could lead to deadlocks.

Fixes the below:

[  223.418794] ======================================================
[  223.418820] WARNING: possible circular locking dependency detected
[  223.418845] 6.12.0-amdstaging-drm-next-lol-050225 #14 Tainted: G     U     OE
[  223.418869] ------------------------------------------------------
[  223.418889] kfdtest/3939 is trying to acquire lock:
[  223.418906] ffff8957552eae38 (&dqm->lock_hidden){+.+.}-{3:3}, at: evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.419302]
               but task is already holding lock:
[  223.419303] ffff8957556b83b0 (&prange->lock){+.+.}-{3:3}, at: svm_range_cpu_invalidate_pagetables+0x9d/0x850 [amdgpu]
[  223.419447] Console: switching to colour dummy device 80x25
[  223.419477] [IGT] amd_basic: executing
[  223.419599]
               which lock already depends on the new lock.

[  223.419611]
               the existing dependency chain (in reverse order) is:
[  223.419621]
               -> #2 (&prange->lock){+.+.}-{3:3}:
[  223.419636]        __mutex_lock+0x85/0xe20
[  223.419647]        mutex_lock_nested+0x1b/0x30
[  223.419656]        svm_range_validate_and_map+0x2f1/0x15b0 [amdgpu]
[  223.419954]        svm_range_set_attr+0xe8c/0x1710 [amdgpu]
[  223.420236]        svm_ioctl+0x46/0x50 [amdgpu]
[  223.420503]        kfd_ioctl_svm+0x50/0x90 [amdgpu]
[  223.420763]        kfd_ioctl+0x409/0x6d0 [amdgpu]
[  223.421024]        __x64_sys_ioctl+0x95/0xd0
[  223.421036]        x64_sys_call+0x1205/0x20d0
[  223.421047]        do_syscall_64+0x87/0x140
[  223.421056]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.421068]
               -> #1 (reservation_ww_class_mutex){+.+.}-{3:3}:
[  223.421084]        __ww_mutex_lock.constprop.0+0xab/0x1560
[  223.421095]        ww_mutex_lock+0x2b/0x90
[  223.421103]        amdgpu_amdkfd_alloc_gtt_mem+0xcc/0x2b0 [amdgpu]
[  223.421361]        add_queue_mes+0x3bc/0x440 [amdgpu]
[  223.421623]        unhalt_cpsch+0x1ae/0x240 [amdgpu]
[  223.421888]        kgd2kfd_start_sched+0x5e/0xd0 [amdgpu]
[  223.422148]        amdgpu_amdkfd_start_sched+0x3d/0x50 [amdgpu]
[  223.422414]        amdgpu_gfx_enforce_isolation_handler+0x132/0x270 [amdgpu]
[  223.422662]        process_one_work+0x21e/0x680
[  223.422673]        worker_thread+0x190/0x330
[  223.422682]        kthread+0xe7/0x120
[  223.422690]        ret_from_fork+0x3c/0x60
[  223.422699]        ret_from_fork_asm+0x1a/0x30
[  223.422708]
               -> #0 (&dqm->lock_hidden){+.+.}-{3:3}:
[  223.422723]        __lock_acquire+0x16f4/0x2810
[  223.422734]        lock_acquire+0xd1/0x300
[  223.422742]        __mutex_lock+0x85/0xe20
[  223.422751]        mutex_lock_nested+0x1b/0x30
[  223.422760]        evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.423025]        kfd_process_evict_queues+0x8a/0x1d0 [amdgpu]
[  223.423285]        kgd2kfd_quiesce_mm+0x43/0x90 [amdgpu]
[  223.423540]        svm_range_cpu_invalidate_pagetables+0x4a7/0x850 [amdgpu]
[  223.423807]        __mmu_notifier_invalidate_range_start+0x1f5/0x250
[  223.423819]        copy_page_range+0x1e94/0x1ea0
[  223.423829]        copy_process+0x172f/0x2ad0
[  223.423839]        kernel_clone+0x9c/0x3f0
[  223.423847]        __do_sys_clone+0x66/0x90
[  223.423856]        __x64_sys_clone+0x25/0x30
[  223.423864]        x64_sys_call+0x1d7c/0x20d0
[  223.423872]        do_syscall_64+0x87/0x140
[  223.423880]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.423891]
               other info that might help us debug this:

[  223.423903] Chain exists of:
                 &dqm->lock_hidden --> reservation_ww_class_mutex --> &prange->lock

[  223.423926]  Possible unsafe locking scenario:

[  223.423935]        CPU0                    CPU1
[  223.423942]        ----                    ----
[  223.423949]   lock(&prange->lock);
[  223.423958]                                lock(reservation_ww_class_mutex);
[  223.423970]                                lock(&prange->lock);
[  223.423981]   lock(&dqm->lock_hidden);
[  223.423990]
                *** DEADLOCK ***

[  223.423999] 5 locks held by kfdtest/3939:
[  223.424006]  #0: ffffffffb82b4fc0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x1387/0x2ad0
[  223.424026]  #1: ffff89575eda81b0 (&mm->mmap_lock){++++}-{3:3}, at: copy_process+0x13a8/0x2ad0
[  223.424046]  #2: ffff89575edaf3b0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_process+0x13e4/0x2ad0
[  223.424066]  #3: ffffffffb82e76e0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: copy_page_range+0x1cea/0x1ea0
[  223.424088]  #4: ffff8957556b83b0 (&prange->lock){+.+.}-{3:3}, at: svm_range_cpu_invalidate_pagetables+0x9d/0x850 [amdgpu]
[  223.424365]
               stack backtrace:
[  223.424374] CPU: 0 UID: 0 PID: 3939 Comm: kfdtest Tainted: G     U     OE      6.12.0-amdstaging-drm-next-lol-050225 #14
[  223.424392] Tainted: [U]=USER, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
[  223.424401] Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS PRO WIFI/X570 AORUS PRO WIFI, BIOS F36a 02/16/2022
[  223.424416] Call Trace:
[  223.424423]  <TASK>
[  223.424430]  dump_stack_lvl+0x9b/0xf0
[  223.424441]  dump_stack+0x10/0x20
[  223.424449]  print_circular_bug+0x275/0x350
[  223.424460]  check_noncircular+0x157/0x170
[  223.424469]  ? __bfs+0xfd/0x2c0
[  223.424481]  __lock_acquire+0x16f4/0x2810
[  223.424490]  ? srso_return_thunk+0x5/0x5f
[  223.424505]  lock_acquire+0xd1/0x300
[  223.424514]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.424783]  __mutex_lock+0x85/0xe20
[  223.424792]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425058]  ? srso_return_thunk+0x5/0x5f
[  223.425067]  ? mark_held_locks+0x54/0x90
[  223.425076]  ? evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425339]  ? srso_return_thunk+0x5/0x5f
[  223.425350]  mutex_lock_nested+0x1b/0x30
[  223.425358]  ? mutex_lock_nested+0x1b/0x30
[  223.425367]  evict_process_queues_cpsch+0x43/0x210 [amdgpu]
[  223.425631]  kfd_process_evict_queues+0x8a/0x1d0 [amdgpu]
[  223.425893]  kgd2kfd_quiesce_mm+0x43/0x90 [amdgpu]
[  223.426156]  svm_range_cpu_invalidate_pagetables+0x4a7/0x850 [amdgpu]
[  223.426423]  ? srso_return_thunk+0x5/0x5f
[  223.426436]  __mmu_notifier_invalidate_range_start+0x1f5/0x250
[  223.426450]  copy_page_range+0x1e94/0x1ea0
[  223.426461]  ? srso_return_thunk+0x5/0x5f
[  223.426474]  ? srso_return_thunk+0x5/0x5f
[  223.426484]  ? lock_acquire+0xd1/0x300
[  223.426494]  ? copy_process+0x1718/0x2ad0
[  223.426502]  ? srso_return_thunk+0x5/0x5f
[  223.426510]  ? sched_clock_noinstr+0x9/0x10
[  223.426519]  ? local_clock_noinstr+0xe/0xc0
[  223.426528]  ? copy_process+0x1718/0x2ad0
[  223.426537]  ? srso_return_thunk+0x5/0x5f
[  223.426550]  copy_process+0x172f/0x2ad0
[  223.426569]  kernel_clone+0x9c/0x3f0
[  223.426577]  ? __schedule+0x4c9/0x1b00
[  223.426586]  ? srso_return_thunk+0x5/0x5f
[  223.426594]  ? sched_clock_noinstr+0x9/0x10
[  223.426602]  ? srso_return_thunk+0x5/0x5f
[  223.426610]  ? local_clock_noinstr+0xe/0xc0
[  223.426619]  ? schedule+0x107/0x1a0
[  223.426629]  __do_sys_clone+0x66/0x90
[  223.426643]  __x64_sys_clone+0x25/0x30
[  223.426652]  x64_sys_call+0x1d7c/0x20d0
[  223.426661]  do_syscall_64+0x87/0x140
[  223.426671]  ? srso_return_thunk+0x5/0x5f
[  223.426679]  ? common_nsleep+0x44/0x50
[  223.426690]  ? srso_return_thunk+0x5/0x5f
[  223.426698]  ? trace_hardirqs_off+0x52/0xd0
[  223.426709]  ? srso_return_thunk+0x5/0x5f
[  223.426717]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426727]  ? srso_return_thunk+0x5/0x5f
[  223.426736]  ? do_syscall_64+0x93/0x140
[  223.426748]  ? srso_return_thunk+0x5/0x5f
[  223.426756]  ? up_write+0x1c/0x1e0
[  223.426765]  ? srso_return_thunk+0x5/0x5f
[  223.426775]  ? srso_return_thunk+0x5/0x5f
[  223.426783]  ? trace_hardirqs_off+0x52/0xd0
[  223.426792]  ? srso_return_thunk+0x5/0x5f
[  223.426800]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426810]  ? srso_return_thunk+0x5/0x5f
[  223.426818]  ? do_syscall_64+0x93/0x140
[  223.426826]  ? syscall_exit_to_user_mode+0xcc/0x200
[  223.426836]  ? srso_return_thunk+0x5/0x5f
[  223.426844]  ? do_syscall_64+0x93/0x140
[  223.426853]  ? srso_return_thunk+0x5/0x5f
[  223.426861]  ? irqentry_exit+0x6b/0x90
[  223.426869]  ? srso_return_thunk+0x5/0x5f
[  223.426877]  ? exc_page_fault+0xa7/0x2c0
[  223.426888]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  223.426898] RIP: 0033:0x7f46758eab57
[  223.426906] Code: ba 04 00 f3 0f 1e fa 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 41 89 c0 85 c0 75 2c 64 48 8b 04 25 10 00
[  223.426930] RSP: 002b:00007fff5c3e5188 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
[  223.426943] RAX: ffffffffffffffda RBX: 00007f4675f8c040 RCX: 00007f46758eab57
[  223.426954] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
[  223.426965] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  223.426975] R10: 00007f4675e81a50 R11: 0000000000000246 R12: 0000000000000001
[  223.426986] R13: 00007fff5c3e5470 R14: 00007fff5c3e53e0 R15: 00007fff5c3e5410
[  223.427004]  </TASK>

v2: To resolve this issue, the allocation of the process context buffer
(`proc_ctx_bo`) has been moved from the `add_queue_mes` function to the
`pqm_create_queue` function. This change ensures that the buffer is
allocated only when the first queue for a process is created and only if
the Micro Engine Scheduler (MES) is enabled. (Felix)

v3: Fix typo s/Memory Execution Scheduler (MES)/Micro Engine Scheduler
in commit message. (Lijo)

Fixes: 438b39a ("drm/amdkfd: pause autosuspend when creating pdd")
Cc: Jesse Zhang <[email protected]>
Cc: Yunxiang Li <[email protected]>
Cc: Philip Yang <[email protected]>
Cc: Alex Sierra <[email protected]>
Cc: Felix Kuehling <[email protected]>
Cc: Christian König <[email protected]>
Cc: Alex Deucher <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
Reviewed-by: Felix Kuehling <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
…cal section

[ Upstream commit 85b2b9c ]

A circular lock dependency splat has been seen involving down_trylock():

  ======================================================
  WARNING: possible circular locking dependency detected
  6.12.0-41.el10.s390x+debug
  ------------------------------------------------------
  dd/32479 is trying to acquire lock:
  0015a20accd0d4f8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x26/0x90

  but task is already holding lock:
  000000017e461698 (&zone->lock){-.-.}-{2:2}, at: rmqueue_bulk+0xac/0x8f0

  the existing dependency chain (in reverse order) is:
  -> #4 (&zone->lock){-.-.}-{2:2}:
  -> #3 (hrtimer_bases.lock){-.-.}-{2:2}:
  -> #2 (&rq->__lock){-.-.}-{2:2}:
  -> #1 (&p->pi_lock){-.-.}-{2:2}:
  -> #0 ((console_sem).lock){-.-.}-{2:2}:

The console_sem -> pi_lock dependency is due to calling try_to_wake_up()
while holding the console_sem raw_spinlock. This dependency can be broken
by using wake_q to do the wakeup instead of calling try_to_wake_up()
under the console_sem lock. This will also make the semaphore's
raw_spinlock become a terminal lock without taking any further locks
underneath it.

The hrtimer_bases.lock is a raw_spinlock while zone->lock is a
spinlock. The hrtimer_bases.lock -> zone->lock dependency happens via
the debug_objects_fill_pool() helper function in the debugobjects code.

  -> #4 (&zone->lock){-.-.}-{2:2}:
         __lock_acquire+0xe86/0x1cc0
         lock_acquire.part.0+0x258/0x630
         lock_acquire+0xb8/0xe0
         _raw_spin_lock_irqsave+0xb4/0x120
         rmqueue_bulk+0xac/0x8f0
         __rmqueue_pcplist+0x580/0x830
         rmqueue_pcplist+0xfc/0x470
         rmqueue.isra.0+0xdec/0x11b0
         get_page_from_freelist+0x2ee/0xeb0
         __alloc_pages_noprof+0x2c2/0x520
         alloc_pages_mpol_noprof+0x1fc/0x4d0
         alloc_pages_noprof+0x8c/0xe0
         allocate_slab+0x320/0x460
         ___slab_alloc+0xa58/0x12b0
         __slab_alloc.isra.0+0x42/0x60
         kmem_cache_alloc_noprof+0x304/0x350
         fill_pool+0xf6/0x450
         debug_object_activate+0xfe/0x360
         enqueue_hrtimer+0x34/0x190
         __run_hrtimer+0x3c8/0x4c0
         __hrtimer_run_queues+0x1b2/0x260
         hrtimer_interrupt+0x316/0x760
         do_IRQ+0x9a/0xe0
         do_irq_async+0xf6/0x160

Normally a raw_spinlock to spinlock dependency is not legitimate
and will be warned if CONFIG_PROVE_RAW_LOCK_NESTING is enabled,
but debug_objects_fill_pool() is an exception as it explicitly
allows this dependency for non-PREEMPT_RT kernel without causing
PROVE_RAW_LOCK_NESTING lockdep splat. As a result, this dependency is
legitimate and not a bug.

Anyway, semaphore is the only locking primitive left that is still
using try_to_wake_up() to do wakeup inside critical section, all the
other locking primitives had been migrated to use wake_q to do wakeup
outside of the critical section. It is also possible that there are
other circular locking dependencies involving printk/console_sem or
other existing/new semaphores lurking somewhere which may show up in
the future. Let just do the migration now to wake_q to avoid headache
like this.

Reported-by: [email protected]
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
[ Upstream commit 053f3ff ]

v2:
- Created a single error handling unlock and exit in veth_pool_store
- Greatly expanded commit message with previous explanatory-only text

Summary: Use rtnl_mutex to synchronize veth_pool_store with itself,
ibmveth_close and ibmveth_open, preventing multiple calls in a row to
napi_disable.

Background: Two (or more) threads could call veth_pool_store through
writing to /sys/devices/vio/30000002/pool*/*. You can do this easily
with a little shell script. This causes a hang.

I configured LOCKDEP, compiled ibmveth.c with DEBUG, and built a new
kernel. I ran this test again and saw:

    Setting pool0/active to 0
    Setting pool1/active to 1
    [   73.911067][ T4365] ibmveth 30000002 eth0: close starting
    Setting pool1/active to 1
    Setting pool1/active to 0
    [   73.911367][ T4366] ibmveth 30000002 eth0: close starting
    [   73.916056][ T4365] ibmveth 30000002 eth0: close complete
    [   73.916064][ T4365] ibmveth 30000002 eth0: open starting
    [  110.808564][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  230.808495][  T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
    [  243.683786][  T123] INFO: task stress.sh:4365 blocked for more than 122 seconds.
    [  243.683827][  T123]       Not tainted 6.14.0-01103-g2df0c02dab82-dirty #8
    [  243.683833][  T123] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    [  243.683838][  T123] task:stress.sh       state:D stack:28096 pid:4365  tgid:4365  ppid:4364   task_flags:0x400040 flags:0x00042000
    [  243.683852][  T123] Call Trace:
    [  243.683857][  T123] [c00000000c38f690] [0000000000000001] 0x1 (unreliable)
    [  243.683868][  T123] [c00000000c38f840] [c00000000001f908] __switch_to+0x318/0x4e0
    [  243.683878][  T123] [c00000000c38f8a0] [c000000001549a70] __schedule+0x500/0x12a0
    [  243.683888][  T123] [c00000000c38f9a0] [c00000000154a878] schedule+0x68/0x210
    [  243.683896][  T123] [c00000000c38f9d0] [c00000000154ac80] schedule_preempt_disabled+0x30/0x50
    [  243.683904][  T123] [c00000000c38fa00] [c00000000154dbb0] __mutex_lock+0x730/0x10f0
    [  243.683913][  T123] [c00000000c38fb10] [c000000001154d40] napi_enable+0x30/0x60
    [  243.683921][  T123] [c00000000c38fb40] [c000000000f4ae94] ibmveth_open+0x68/0x5dc
    [  243.683928][  T123] [c00000000c38fbe0] [c000000000f4aa20] veth_pool_store+0x220/0x270
    [  243.683936][  T123] [c00000000c38fc70] [c000000000826278] sysfs_kf_write+0x68/0xb0
    [  243.683944][  T123] [c00000000c38fcb0] [c0000000008240b8] kernfs_fop_write_iter+0x198/0x2d0
    [  243.683951][  T123] [c00000000c38fd00] [c00000000071b9ac] vfs_write+0x34c/0x650
    [  243.683958][  T123] [c00000000c38fdc0] [c00000000071bea8] ksys_write+0x88/0x150
    [  243.683966][  T123] [c00000000c38fe10] [c0000000000317f4] system_call_exception+0x124/0x340
    [  243.683973][  T123] [c00000000c38fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
    ...
    [  243.684087][  T123] Showing all locks held in the system:
    [  243.684095][  T123] 1 lock held by khungtaskd/123:
    [  243.684099][  T123]  #0: c00000000278e370 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x50/0x248
    [  243.684114][  T123] 4 locks held by stress.sh/4365:
    [  243.684119][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684132][  T123]  #1: c000000041aea888 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684143][  T123]  #2: c0000000366fb9a8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684155][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_enable+0x30/0x60
    [  243.684166][  T123] 5 locks held by stress.sh/4366:
    [  243.684170][  T123]  #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
    [  243.684183][  T123]  #1: c00000000aee2288 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
    [  243.684194][  T123]  #2: c0000000366f4ba8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
    [  243.684205][  T123]  #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_disable+0x30/0x60
    [  243.684216][  T123]  #4: c0000003ff9bbf18 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x138/0x12a0

From the ibmveth debug, two threads are calling veth_pool_store, which
calls ibmveth_close and ibmveth_open. Here's the sequence:

  T4365             T4366
  ----------------- ----------------- ---------
  veth_pool_store   veth_pool_store
                    ibmveth_close
  ibmveth_close
  napi_disable
                    napi_disable
  ibmveth_open
  napi_enable                         <- HANG

ibmveth_close calls napi_disable at the top and ibmveth_open calls
napi_enable at the top.

https://docs.kernel.org/networking/napi.html]] says

  The control APIs are not idempotent. Control API calls are safe
  against concurrent use of datapath APIs but an incorrect sequence of
  control API calls may result in crashes, deadlocks, or race
  conditions. For example, calling napi_disable() multiple times in a
  row will deadlock.

In the normal open and close paths, rtnl_mutex is acquired to prevent
other callers. This is missing from veth_pool_store. Use rtnl_mutex in
veth_pool_store fixes these hangs.

Signed-off-by: Dave Marquardt <[email protected]>
Fixes: 860f242 ("[PATCH] ibmveth change buffer pools dynamically")
Reviewed-by: Nick Child <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
[ Upstream commit b61e69b ]

syzbot report a deadlock in diFree. [1]

When calling "ioctl$LOOP_SET_STATUS64", the offset value passed in is 4,
which does not match the mounted loop device, causing the mapping of the
mounted loop device to be invalidated.

When creating the directory and creating the inode of iag in diReadSpecial(),
read the page of fixed disk inode (AIT) in raw mode in read_metapage(), the
metapage data it returns is corrupted, which causes the nlink value of 0 to be
assigned to the iag inode when executing copy_from_dinode(), which ultimately
causes a deadlock when entering diFree().

To avoid this, first check the nlink value of dinode before setting iag inode.

[1]
WARNING: possible recursive locking detected
6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0 Not tainted
--------------------------------------------
syz-executor301/5309 is trying to acquire lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889

but task is already holding lock:
ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(imap->im_aglock[index]));
  lock(&(imap->im_aglock[index]));

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor301/5309:
 #0: ffff8880422a4420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:850 [inline]
 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x260/0x540 fs/namei.c:4026
 #2: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2460 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocAG+0x4b7/0x1e50 fs/jfs/jfs_imap.c:1669
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2477 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocAG+0x869/0x1e50 fs/jfs/jfs_imap.c:1669

stack backtrace:
CPU: 0 UID: 0 PID: 5309 Comm: syz-executor301 Not tainted 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889
 jfs_evict_inode+0x32d/0x440 fs/jfs/inode.c:156
 evict+0x4e8/0x9b0 fs/inode.c:725
 diFreeSpecial fs/jfs/jfs_imap.c:552 [inline]
 duplicateIXtree+0x3c6/0x550 fs/jfs/jfs_imap.c:3022
 diNewIAG fs/jfs/jfs_imap.c:2597 [inline]
 diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 diAllocAG+0x17dc/0x1e50 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d2/0x1630 fs/jfs/jfs_imap.c:1590
 ialloc+0x8f/0x900 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x1c5/0xba0 fs/jfs/namei.c:225
 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
 do_mkdirat+0x264/0x3a0 fs/namei.c:4280
 __do_sys_mkdirat fs/namei.c:4295 [inline]
 __se_sys_mkdirat fs/namei.c:4293 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=355da3b3a74881008e8f
Signed-off-by: Edward Adam Davis <[email protected]>
Signed-off-by: Dave Kleikamp <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
commit 2ccd42b upstream.

If we finds a vq without a name in our input array in
virtio_ccw_find_vqs(), we treat it as "non-existing" and set the vq pointer
to NULL; we will not call virtio_ccw_setup_vq() to allocate/setup a vq.

Consequently, we create only a queue if it actually exists (name != NULL)
and assign an incremental queue index to each such existing queue.

However, in virtio_ccw_register_adapter_ind()->get_airq_indicator() we
will not ignore these "non-existing queues", but instead assign an airq
indicator to them.

Besides never releasing them in virtio_ccw_drop_indicators() (because
there is no virtqueue), the bigger issue seems to be that there will be a
disagreement between the device and the Linux guest about the airq
indicator to be used for notifying a queue, because the indicator bit
for adapter I/O interrupt is derived from the queue index.

The virtio spec states under "Setting Up Two-Stage Queue Indicators":

	... indicator contains the guest address of an area wherein the
	indicators for the devices are contained, starting at bit_nr, one
	bit per virtqueue of the device.

And further in "Notification via Adapter I/O Interrupts":

	For notifying the driver of virtqueue buffers, the device sets the
	bit in the guest-provided indicator area at the corresponding
	offset.

For example, QEMU uses in virtio_ccw_notify() the queue index (passed as
"vector") to select the relevant indicator bit. If a queue does not exist,
it does not have a corresponding indicator bit assigned, because it
effectively doesn't have a queue index.

Using a virtio-balloon-ccw device under QEMU with free-page-hinting
disabled ("free-page-hint=off") but free-page-reporting enabled
("free-page-reporting=on") will result in free page reporting
not working as expected: in the virtio_balloon driver, we'll be stuck
forever in virtballoon_free_page_report()->wait_event(), because the
waitqueue will not be woken up as the notification from the device is
lost: it would use the wrong indicator bit.

Free page reporting stops working and we get splats (when configured to
detect hung wqs) like:

 INFO: task kworker/1:3:463 blocked for more than 61 seconds.
       Not tainted 6.14.0 #4
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:kworker/1:3 [...]
 Workqueue: events page_reporting_process
 Call Trace:
  [<000002f404e6dfb2>] __schedule+0x402/0x1640
  [<000002f404e6f22e>] schedule+0x3e/0xe0
  [<000002f3846a88fa>] virtballoon_free_page_report+0xaa/0x110 [virtio_balloon]
  [<000002f40435c8a4>] page_reporting_process+0x2e4/0x740
  [<000002f403fd3ee2>] process_one_work+0x1c2/0x400
  [<000002f403fd4b96>] worker_thread+0x296/0x420
  [<000002f403fe10b4>] kthread+0x124/0x290
  [<000002f403f4e0dc>] __ret_from_fork+0x3c/0x60
  [<000002f404e77272>] ret_from_fork+0xa/0x38

There was recently a discussion [1] whether the "holes" should be
treated differently again, effectively assigning also non-existing
queues a queue index: that should also fix the issue, but requires other
workarounds to not break existing setups.

Let's fix it without affecting existing setups for now by properly ignoring
the non-existing queues, so the indicator bits will match the queue
indexes.

[1] https://lore.kernel.org/all/[email protected]/

Fixes: a229989 ("virtio: don't allocate vqs when names[i] = NULL")
Reported-by: Chandra Merla <[email protected]>
Cc: [email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Tested-by: Thomas Huth <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
commit 366e77c upstream.

Commit 7da55c2 ("drm/amd/display: Remove incorrect FP context
start") removes the FP context protection of dml2_create(), and it said
"All the DC_FP_START/END should be used before call anything from DML2".

However, dml2_validate()/dml21_validate() are not protected from their
callers, causing such errors:

 do_fpu invoked from kernel context![#1]:
 CPU: 10 UID: 0 PID: 331 Comm: kworker/10:1H Not tainted 6.14.0-rc6+ #4
 Workqueue: events_highpri dm_irq_work_func [amdgpu]
 pc ffff800003191eb0 ra ffff800003191e60 tp 9000000107a94000 sp 9000000107a975b0
 a0 9000000140ce4910 a1 0000000000000000 a2 9000000140ce49b0 a3 9000000140ce49a8
 a4 9000000140ce49a8 a5 0000000100000000 a6 0000000000000001 a7 9000000107a97660
 t0 ffff800003790000 t1 9000000140ce5000 t2 0000000000000001 t3 0000000000000000
 t4 0000000000000004 t5 0000000000000000 t6 0000000000000000 t7 0000000000000000
 t8 0000000100000000 u0 ffff8000031a3b9c s9 9000000130bc0000 s0 9000000132400000
 s1 9000000140ec0000 s2 9000000132400000 s3 9000000140ce0000 s4 90000000057f8b88
 s5 9000000140ec0000 s6 9000000140ce4910 s7 0000000000000001 s8 9000000130d45010
 ra: ffff800003191e60 dml21_map_dc_state_into_dml_display_cfg+0x40/0x1140 [amdgpu]
   ERA: ffff800003191eb0 dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  PRMD: 00000004 (PPLV0 +PIE -PWE)
  EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
  ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
 ESTAT: 000f0000 [FPD] (IS= ECode=15 EsubCode=0)
  PRID: 0014d010 (Loongson-64bit, Loongson-3C6000/S)
 Process kworker/10:1H (pid: 331, threadinfo=000000007bf9ddb0, task=00000000cc4ab9f3)
 Stack : 0000000100000000 0000043800000780 0000000100000001 0000000100000001
         0000000000000000 0000078000000000 0000000000000438 0000078000000000
         0000000000000438 0000078000000000 0000000000000438 0000000100000000
         0000000100000000 0000000100000000 0000000100000000 0000000100000000
         0000000000000001 9000000140ec0000 9000000132400000 9000000132400000
         ffff800003408000 ffff800003408000 9000000132400000 9000000140ce0000
         9000000140ce0000 ffff800003193850 0000000000000001 9000000140ec0000
         9000000132400000 9000000140ec0860 9000000140ec0738 0000000000000001
         90000001405e8000 9000000130bc0000 9000000140ec02a8 ffff8000031b5db8
         0000000000000000 0000043800000780 0000000000000003 ffff8000031b79cc
         ...
 Call Trace:
 [<ffff800003191eb0>] dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
 [<ffff80000319384c>] dml21_validate+0xcc/0x520 [amdgpu]
 [<ffff8000031b8948>] dc_validate_global_state+0x2e8/0x460 [amdgpu]
 [<ffff800002e94034>] create_validate_stream_for_sink+0x3d4/0x420 [amdgpu]
 [<ffff800002e940e4>] amdgpu_dm_connector_mode_valid+0x64/0x240 [amdgpu]
 [<900000000441d6b8>] drm_connector_mode_valid+0x38/0x80
 [<900000000441d824>] __drm_helper_update_and_validate+0x124/0x3e0
 [<900000000441ddc0>] drm_helper_probe_single_connector_modes+0x2e0/0x620
 [<90000000044050dc>] drm_client_modeset_probe+0x23c/0x1780
 [<9000000004420384>] __drm_fb_helper_initial_config_and_unlock+0x44/0x5a0
 [<9000000004403acc>] drm_client_dev_hotplug+0xcc/0x140
 [<ffff800002e9ab50>] handle_hpd_irq_helper+0x1b0/0x1e0 [amdgpu]
 [<90000000038f5da0>] process_one_work+0x160/0x300
 [<90000000038f6718>] worker_thread+0x318/0x440
 [<9000000003901b8c>] kthread+0x12c/0x220
 [<90000000038b1484>] ret_from_kernel_thread+0x8/0xa4

Unfortunately, protecting dml2_validate()/dml21_validate() out of DML2
causes "sleeping function called from invalid context", so protect them
with DC_FP_START() and DC_FP_END() inside.

Fixes: 7da55c2 ("drm/amd/display: Remove incorrect FP context start")
Cc: [email protected]
Signed-off-by: Huacai Chen <[email protected]>
Tested-by: Dongyan Qian <[email protected]>
Reviewed-by: Aurabindo Pillai <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 28, 2025
commit 366e77c upstream.

Commit 7da55c2 ("drm/amd/display: Remove incorrect FP context
start") removes the FP context protection of dml2_create(), and it said
"All the DC_FP_START/END should be used before call anything from DML2".

However, dml2_validate()/dml21_validate() are not protected from their
callers, causing such errors:

 do_fpu invoked from kernel context![#1]:
 CPU: 10 UID: 0 PID: 331 Comm: kworker/10:1H Not tainted 6.14.0-rc6+ #4
 Workqueue: events_highpri dm_irq_work_func [amdgpu]
 pc ffff800003191eb0 ra ffff800003191e60 tp 9000000107a94000 sp 9000000107a975b0
 a0 9000000140ce4910 a1 0000000000000000 a2 9000000140ce49b0 a3 9000000140ce49a8
 a4 9000000140ce49a8 a5 0000000100000000 a6 0000000000000001 a7 9000000107a97660
 t0 ffff800003790000 t1 9000000140ce5000 t2 0000000000000001 t3 0000000000000000
 t4 0000000000000004 t5 0000000000000000 t6 0000000000000000 t7 0000000000000000
 t8 0000000100000000 u0 ffff8000031a3b9c s9 9000000130bc0000 s0 9000000132400000
 s1 9000000140ec0000 s2 9000000132400000 s3 9000000140ce0000 s4 90000000057f8b88
 s5 9000000140ec0000 s6 9000000140ce4910 s7 0000000000000001 s8 9000000130d45010
 ra: ffff800003191e60 dml21_map_dc_state_into_dml_display_cfg+0x40/0x1140 [amdgpu]
   ERA: ffff800003191eb0 dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  PRMD: 00000004 (PPLV0 +PIE -PWE)
  EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
  ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
 ESTAT: 000f0000 [FPD] (IS= ECode=15 EsubCode=0)
  PRID: 0014d010 (Loongson-64bit, Loongson-3C6000/S)
 Process kworker/10:1H (pid: 331, threadinfo=000000007bf9ddb0, task=00000000cc4ab9f3)
 Stack : 0000000100000000 0000043800000780 0000000100000001 0000000100000001
         0000000000000000 0000078000000000 0000000000000438 0000078000000000
         0000000000000438 0000078000000000 0000000000000438 0000000100000000
         0000000100000000 0000000100000000 0000000100000000 0000000100000000
         0000000000000001 9000000140ec0000 9000000132400000 9000000132400000
         ffff800003408000 ffff800003408000 9000000132400000 9000000140ce0000
         9000000140ce0000 ffff800003193850 0000000000000001 9000000140ec0000
         9000000132400000 9000000140ec0860 9000000140ec0738 0000000000000001
         90000001405e8000 9000000130bc0000 9000000140ec02a8 ffff8000031b5db8
         0000000000000000 0000043800000780 0000000000000003 ffff8000031b79cc
         ...
 Call Trace:
 [<ffff800003191eb0>] dml21_map_dc_state_into_dml_display_cfg+0x90/0x1140 [amdgpu]
 [<ffff80000319384c>] dml21_validate+0xcc/0x520 [amdgpu]
 [<ffff8000031b8948>] dc_validate_global_state+0x2e8/0x460 [amdgpu]
 [<ffff800002e94034>] create_validate_stream_for_sink+0x3d4/0x420 [amdgpu]
 [<ffff800002e940e4>] amdgpu_dm_connector_mode_valid+0x64/0x240 [amdgpu]
 [<900000000441d6b8>] drm_connector_mode_valid+0x38/0x80
 [<900000000441d824>] __drm_helper_update_and_validate+0x124/0x3e0
 [<900000000441ddc0>] drm_helper_probe_single_connector_modes+0x2e0/0x620
 [<90000000044050dc>] drm_client_modeset_probe+0x23c/0x1780
 [<9000000004420384>] __drm_fb_helper_initial_config_and_unlock+0x44/0x5a0
 [<9000000004403acc>] drm_client_dev_hotplug+0xcc/0x140
 [<ffff800002e9ab50>] handle_hpd_irq_helper+0x1b0/0x1e0 [amdgpu]
 [<90000000038f5da0>] process_one_work+0x160/0x300
 [<90000000038f6718>] worker_thread+0x318/0x440
 [<9000000003901b8c>] kthread+0x12c/0x220
 [<90000000038b1484>] ret_from_kernel_thread+0x8/0xa4

Unfortunately, protecting dml2_validate()/dml21_validate() out of DML2
causes "sleeping function called from invalid context", so protect them
with DC_FP_START() and DC_FP_END() inside.

Fixes: 7da55c2 ("drm/amd/display: Remove incorrect FP context start")
Cc: [email protected]
Signed-off-by: Huacai Chen <[email protected]>
Tested-by: Dongyan Qian <[email protected]>
Reviewed-by: Aurabindo Pillai <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 28, 2025
There is a potential deadlock if we do report zones in an IO context, detailed
in below lockdep report. When one process do a report zones and another process
freezes the block device, the report zones side cannot allocate a tag because
the freeze is already started. This can thus result in new block group creation
to hang forever, blocking the write path.

Thankfully, a new block group should be created on empty zones. So, reporting
the zones is not necessary and we can set the write pointer = 0 and load the
zone capacity from the block layer using bdev_zone_capacity() helper.

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc1 #252 Not tainted
 ------------------------------------------------------
 modprobe/1110 is trying to acquire lock:
 ffff888100ac83e0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x38f/0xb60

 but task is already holding lock:
 ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&q->q_usage_counter(queue)#16){++++}-{0:0}:
        blk_queue_enter+0x3d9/0x500
        blk_mq_alloc_request+0x47d/0x8e0
        scsi_execute_cmd+0x14f/0xb80
        sd_zbc_do_report_zones+0x1c1/0x470
        sd_zbc_report_zones+0x362/0xd60
        blkdev_report_zones+0x1b1/0x2e0
        btrfs_get_dev_zones+0x215/0x7e0 [btrfs]
        btrfs_load_block_group_zone_info+0x6d2/0x2c10 [btrfs]
        btrfs_make_block_group+0x36b/0x870 [btrfs]
        btrfs_create_chunk+0x147d/0x2320 [btrfs]
        btrfs_chunk_alloc+0x2ce/0xcf0 [btrfs]
        start_transaction+0xce6/0x1620 [btrfs]
        btrfs_uuid_scan_kthread+0x4ee/0x5b0 [btrfs]
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&fs_info->dev_replace.rwsem){++++}-{4:4}:
        down_read+0x9b/0x470
        btrfs_map_block+0x2ce/0x2ce0 [btrfs]
        btrfs_submit_chunk+0x2d4/0x16c0 [btrfs]
        btrfs_submit_bbio+0x16/0x30 [btrfs]
        btree_write_cache_pages+0xb5a/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&fs_info->zoned_meta_io_lock){+.+.}-{4:4}:
        __mutex_lock+0x1aa/0x1360
        btree_write_cache_pages+0x252/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
        __lock_acquire+0x2f52/0x5ea0
        lock_acquire+0x1b1/0x540
        __flush_work+0x3ac/0xb60
        wb_shutdown+0x15b/0x1f0
        bdi_unregister+0x172/0x5b0
        del_gendisk+0x841/0xa20
        sd_remove+0x85/0x130
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        __scsi_remove_device+0x272/0x340
        scsi_forget_host+0xf7/0x170
        scsi_remove_host+0xd2/0x2a0
        sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        device_unregister+0x13/0xa0
        sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
        scsi_debug_exit+0x17/0x70 [scsi_debug]
        __do_sys_delete_module.isra.0+0x321/0x520
        do_syscall_64+0x93/0x180
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   (work_completion)(&(&wb->dwork)->work) --> &fs_info->dev_replace.rwsem --> &q->q_usage_counter(queue)#16

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&q->q_usage_counter(queue)#16);
                                lock(&fs_info->dev_replace.rwsem);
                                lock(&q->q_usage_counter(queue)#16);
   lock((work_completion)(&(&wb->dwork)->work));

  *** DEADLOCK ***

 5 locks held by modprobe/1110:
  #0: ffff88811f7bc108 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #1: ffff8881022ee0e0 (&shost->scan_mutex){+.+.}-{4:4}, at: scsi_remove_host+0x20/0x2a0
  #2: ffff88811b4c4378 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #3: ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130
  #4: ffffffffa3284360 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xda/0xb60

 stack backtrace:
 CPU: 0 UID: 0 PID: 1110 Comm: modprobe Not tainted 6.14.0-rc1 #252
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6a/0x90
  print_circular_bug.cold+0x1e0/0x274
  check_noncircular+0x306/0x3f0
  ? __pfx_check_noncircular+0x10/0x10
  ? mark_lock+0xf5/0x1650
  ? __pfx_check_irq_usage+0x10/0x10
  ? lockdep_lock+0xca/0x1c0
  ? __pfx_lockdep_lock+0x10/0x10
  __lock_acquire+0x2f52/0x5ea0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx_mark_lock+0x10/0x10
  lock_acquire+0x1b1/0x540
  ? __flush_work+0x38f/0xb60
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  ? __flush_work+0x38f/0xb60
  __flush_work+0x3ac/0xb60
  ? __flush_work+0x38f/0xb60
  ? __pfx_mark_lock+0x10/0x10
  ? __pfx___flush_work+0x10/0x10
  ? __pfx_wq_barrier_func+0x10/0x10
  ? __pfx___might_resched+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  wb_shutdown+0x15b/0x1f0
  bdi_unregister+0x172/0x5b0
  ? __pfx_bdi_unregister+0x10/0x10
  ? up_write+0x1ba/0x510
  del_gendisk+0x841/0xa20
  ? __pfx_del_gendisk+0x10/0x10
  ? _raw_spin_unlock_irqrestore+0x35/0x60
  ? __pm_runtime_resume+0x79/0x110
  sd_remove+0x85/0x130
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  __scsi_remove_device+0x272/0x340
  scsi_forget_host+0xf7/0x170
  scsi_remove_host+0xd2/0x2a0
  sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
  ? kernfs_remove_by_name_ns+0xc0/0xf0
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  ? __pfx___mutex_unlock_slowpath+0x10/0x10
  device_unregister+0x13/0xa0
  sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
  scsi_debug_exit+0x17/0x70 [scsi_debug]
  __do_sys_delete_module.isra.0+0x321/0x520
  ? __pfx___do_sys_delete_module.isra.0+0x10/0x10
  ? __pfx_slab_free_after_rcu_debug+0x10/0x10
  ? kasan_save_stack+0x2c/0x50
  ? kasan_record_aux_stack+0xa3/0xb0
  ? __call_rcu_common.constprop.0+0xc4/0xfb0
  ? kmem_cache_free+0x3a0/0x590
  ? __x64_sys_close+0x78/0xd0
  do_syscall_64+0x93/0x180
  ? lock_is_held_type+0xd5/0x130
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? lockdep_hardirqs_on+0x78/0x100
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? __pfx___call_rcu_common.constprop.0+0x10/0x10
  ? kmem_cache_free+0x3a0/0x590
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  ? __pfx___x64_sys_openat+0x10/0x10
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f436712b68b
 RSP: 002b:00007ffe9f1a8658 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
 RAX: ffffffffffffffda RBX: 00005559b367fd80 RCX: 00007f436712b68b
 RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00005559b367fde8
 RBP: 00007ffe9f1a8680 R08: 1999999999999999 R09: 0000000000000000
 R10: 00007f43671a5fe0 R11: 0000000000000206 R12: 0000000000000000
 R13: 00007ffe9f1a86b0 R14: 0000000000000000 R15: 0000000000000000
  </TASK>

Reported-by: Shin'ichiro Kawasaki <[email protected]>
CC: <[email protected]> # 6.13+
Tested-by: Shin'ichiro Kawasaki <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Naohiro Aota <[email protected]>
Signed-off-by: David Sterba <[email protected]>
popcornmix pushed a commit that referenced this issue May 14, 2025
[ Upstream commit 866bafa ]

There is a potential deadlock if we do report zones in an IO context, detailed
in below lockdep report. When one process do a report zones and another process
freezes the block device, the report zones side cannot allocate a tag because
the freeze is already started. This can thus result in new block group creation
to hang forever, blocking the write path.

Thankfully, a new block group should be created on empty zones. So, reporting
the zones is not necessary and we can set the write pointer = 0 and load the
zone capacity from the block layer using bdev_zone_capacity() helper.

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc1 #252 Not tainted
 ------------------------------------------------------
 modprobe/1110 is trying to acquire lock:
 ffff888100ac83e0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x38f/0xb60

 but task is already holding lock:
 ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&q->q_usage_counter(queue)#16){++++}-{0:0}:
        blk_queue_enter+0x3d9/0x500
        blk_mq_alloc_request+0x47d/0x8e0
        scsi_execute_cmd+0x14f/0xb80
        sd_zbc_do_report_zones+0x1c1/0x470
        sd_zbc_report_zones+0x362/0xd60
        blkdev_report_zones+0x1b1/0x2e0
        btrfs_get_dev_zones+0x215/0x7e0 [btrfs]
        btrfs_load_block_group_zone_info+0x6d2/0x2c10 [btrfs]
        btrfs_make_block_group+0x36b/0x870 [btrfs]
        btrfs_create_chunk+0x147d/0x2320 [btrfs]
        btrfs_chunk_alloc+0x2ce/0xcf0 [btrfs]
        start_transaction+0xce6/0x1620 [btrfs]
        btrfs_uuid_scan_kthread+0x4ee/0x5b0 [btrfs]
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&fs_info->dev_replace.rwsem){++++}-{4:4}:
        down_read+0x9b/0x470
        btrfs_map_block+0x2ce/0x2ce0 [btrfs]
        btrfs_submit_chunk+0x2d4/0x16c0 [btrfs]
        btrfs_submit_bbio+0x16/0x30 [btrfs]
        btree_write_cache_pages+0xb5a/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&fs_info->zoned_meta_io_lock){+.+.}-{4:4}:
        __mutex_lock+0x1aa/0x1360
        btree_write_cache_pages+0x252/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
        __lock_acquire+0x2f52/0x5ea0
        lock_acquire+0x1b1/0x540
        __flush_work+0x3ac/0xb60
        wb_shutdown+0x15b/0x1f0
        bdi_unregister+0x172/0x5b0
        del_gendisk+0x841/0xa20
        sd_remove+0x85/0x130
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        __scsi_remove_device+0x272/0x340
        scsi_forget_host+0xf7/0x170
        scsi_remove_host+0xd2/0x2a0
        sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        device_unregister+0x13/0xa0
        sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
        scsi_debug_exit+0x17/0x70 [scsi_debug]
        __do_sys_delete_module.isra.0+0x321/0x520
        do_syscall_64+0x93/0x180
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   (work_completion)(&(&wb->dwork)->work) --> &fs_info->dev_replace.rwsem --> &q->q_usage_counter(queue)#16

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&q->q_usage_counter(queue)#16);
                                lock(&fs_info->dev_replace.rwsem);
                                lock(&q->q_usage_counter(queue)#16);
   lock((work_completion)(&(&wb->dwork)->work));

  *** DEADLOCK ***

 5 locks held by modprobe/1110:
  #0: ffff88811f7bc108 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #1: ffff8881022ee0e0 (&shost->scan_mutex){+.+.}-{4:4}, at: scsi_remove_host+0x20/0x2a0
  #2: ffff88811b4c4378 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #3: ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130
  #4: ffffffffa3284360 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xda/0xb60

 stack backtrace:
 CPU: 0 UID: 0 PID: 1110 Comm: modprobe Not tainted 6.14.0-rc1 #252
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6a/0x90
  print_circular_bug.cold+0x1e0/0x274
  check_noncircular+0x306/0x3f0
  ? __pfx_check_noncircular+0x10/0x10
  ? mark_lock+0xf5/0x1650
  ? __pfx_check_irq_usage+0x10/0x10
  ? lockdep_lock+0xca/0x1c0
  ? __pfx_lockdep_lock+0x10/0x10
  __lock_acquire+0x2f52/0x5ea0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx_mark_lock+0x10/0x10
  lock_acquire+0x1b1/0x540
  ? __flush_work+0x38f/0xb60
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  ? __flush_work+0x38f/0xb60
  __flush_work+0x3ac/0xb60
  ? __flush_work+0x38f/0xb60
  ? __pfx_mark_lock+0x10/0x10
  ? __pfx___flush_work+0x10/0x10
  ? __pfx_wq_barrier_func+0x10/0x10
  ? __pfx___might_resched+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  wb_shutdown+0x15b/0x1f0
  bdi_unregister+0x172/0x5b0
  ? __pfx_bdi_unregister+0x10/0x10
  ? up_write+0x1ba/0x510
  del_gendisk+0x841/0xa20
  ? __pfx_del_gendisk+0x10/0x10
  ? _raw_spin_unlock_irqrestore+0x35/0x60
  ? __pm_runtime_resume+0x79/0x110
  sd_remove+0x85/0x130
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  __scsi_remove_device+0x272/0x340
  scsi_forget_host+0xf7/0x170
  scsi_remove_host+0xd2/0x2a0
  sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
  ? kernfs_remove_by_name_ns+0xc0/0xf0
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  ? __pfx___mutex_unlock_slowpath+0x10/0x10
  device_unregister+0x13/0xa0
  sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
  scsi_debug_exit+0x17/0x70 [scsi_debug]
  __do_sys_delete_module.isra.0+0x321/0x520
  ? __pfx___do_sys_delete_module.isra.0+0x10/0x10
  ? __pfx_slab_free_after_rcu_debug+0x10/0x10
  ? kasan_save_stack+0x2c/0x50
  ? kasan_record_aux_stack+0xa3/0xb0
  ? __call_rcu_common.constprop.0+0xc4/0xfb0
  ? kmem_cache_free+0x3a0/0x590
  ? __x64_sys_close+0x78/0xd0
  do_syscall_64+0x93/0x180
  ? lock_is_held_type+0xd5/0x130
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? lockdep_hardirqs_on+0x78/0x100
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? __pfx___call_rcu_common.constprop.0+0x10/0x10
  ? kmem_cache_free+0x3a0/0x590
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  ? __pfx___x64_sys_openat+0x10/0x10
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f436712b68b
 RSP: 002b:00007ffe9f1a8658 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
 RAX: ffffffffffffffda RBX: 00005559b367fd80 RCX: 00007f436712b68b
 RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00005559b367fde8
 RBP: 00007ffe9f1a8680 R08: 1999999999999999 R09: 0000000000000000
 R10: 00007f43671a5fe0 R11: 0000000000000206 R12: 0000000000000000
 R13: 00007ffe9f1a86b0 R14: 0000000000000000 R15: 0000000000000000
  </TASK>

Reported-by: Shin'ichiro Kawasaki <[email protected]>
CC: <[email protected]> # 6.13+
Tested-by: Shin'ichiro Kawasaki <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Naohiro Aota <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue May 14, 2025
When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below.  To prevent this invalid access, it is necessary to
check the PMD migration entry and return early.  In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio.  Since the PMD migration entry is locked, it
cannot be served as the target.

Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."

BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 84c3fc4 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Gavin Guo <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Acked-by: Zi Yan <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Cc: Florent Revest <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
popcornmix pushed a commit that referenced this issue May 20, 2025
A warning on driver removal started occurring after commit 9dd05df
("net: warn if NAPI instance wasn't shut down"). Disable tx napi before
deleting it in mt76_dma_cleanup().

 WARNING: CPU: 4 PID: 18828 at net/core/dev.c:7288 __netif_napi_del_locked+0xf0/0x100
 CPU: 4 UID: 0 PID: 18828 Comm: modprobe Not tainted 6.15.0-rc4 #4 PREEMPT(lazy)
 Hardware name: ASUS System Product Name/PRIME X670E-PRO WIFI, BIOS 3035 09/05/2024
 RIP: 0010:__netif_napi_del_locked+0xf0/0x100
 Call Trace:
 <TASK>
 mt76_dma_cleanup+0x54/0x2f0 [mt76]
 mt7921_pci_remove+0xd5/0x190 [mt7921e]
 pci_device_remove+0x47/0xc0
 device_release_driver_internal+0x19e/0x200
 driver_detach+0x48/0x90
 bus_remove_driver+0x6d/0xf0
 pci_unregister_driver+0x2e/0xb0
 __do_sys_delete_module.isra.0+0x197/0x2e0
 do_syscall_64+0x7b/0x160
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Tested with mt7921e but the same pattern can be actually applied to other
mt76 drivers calling mt76_dma_cleanup() during removal. Tx napi is enabled
in their *_dma_init() functions and only toggled off and on again inside
their suspend/resume/reset paths. So it should be okay to disable tx
napi in such a generic way.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 2ac515a ("mt76: mt76x02: use napi polling for tx cleanup")
Cc: [email protected]
Signed-off-by: Fedor Pchelkin <[email protected]>
Tested-by: Ming Yen Hsieh <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>
popcornmix pushed a commit that referenced this issue May 20, 2025
commit be6e843 upstream.

When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below.  To prevent this invalid access, it is necessary to
check the PMD migration entry and return early.  In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio.  Since the PMD migration entry is locked, it
cannot be served as the target.

Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."

BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 84c3fc4 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Gavin Guo <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Acked-by: Zi Yan <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Cc: Florent Revest <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue May 20, 2025
commit be6e843 upstream.

When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below.  To prevent this invalid access, it is necessary to
check the PMD migration entry and return early.  In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio.  Since the PMD migration entry is locked, it
cannot be served as the target.

Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."

BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 84c3fc4 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Gavin Guo <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Acked-by: Zi Yan <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Cc: Florent Revest <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue May 23, 2025
commit 78ab4be upstream.

A warning on driver removal started occurring after commit 9dd05df
("net: warn if NAPI instance wasn't shut down"). Disable tx napi before
deleting it in mt76_dma_cleanup().

 WARNING: CPU: 4 PID: 18828 at net/core/dev.c:7288 __netif_napi_del_locked+0xf0/0x100
 CPU: 4 UID: 0 PID: 18828 Comm: modprobe Not tainted 6.15.0-rc4 #4 PREEMPT(lazy)
 Hardware name: ASUS System Product Name/PRIME X670E-PRO WIFI, BIOS 3035 09/05/2024
 RIP: 0010:__netif_napi_del_locked+0xf0/0x100
 Call Trace:
 <TASK>
 mt76_dma_cleanup+0x54/0x2f0 [mt76]
 mt7921_pci_remove+0xd5/0x190 [mt7921e]
 pci_device_remove+0x47/0xc0
 device_release_driver_internal+0x19e/0x200
 driver_detach+0x48/0x90
 bus_remove_driver+0x6d/0xf0
 pci_unregister_driver+0x2e/0xb0
 __do_sys_delete_module.isra.0+0x197/0x2e0
 do_syscall_64+0x7b/0x160
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Tested with mt7921e but the same pattern can be actually applied to other
mt76 drivers calling mt76_dma_cleanup() during removal. Tx napi is enabled
in their *_dma_init() functions and only toggled off and on again inside
their suspend/resume/reset paths. So it should be okay to disable tx
napi in such a generic way.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 2ac515a ("mt76: mt76x02: use napi polling for tx cleanup")
Cc: [email protected]
Signed-off-by: Fedor Pchelkin <[email protected]>
Tested-by: Ming Yen Hsieh <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue May 23, 2025
commit 78ab4be upstream.

A warning on driver removal started occurring after commit 9dd05df
("net: warn if NAPI instance wasn't shut down"). Disable tx napi before
deleting it in mt76_dma_cleanup().

 WARNING: CPU: 4 PID: 18828 at net/core/dev.c:7288 __netif_napi_del_locked+0xf0/0x100
 CPU: 4 UID: 0 PID: 18828 Comm: modprobe Not tainted 6.15.0-rc4 #4 PREEMPT(lazy)
 Hardware name: ASUS System Product Name/PRIME X670E-PRO WIFI, BIOS 3035 09/05/2024
 RIP: 0010:__netif_napi_del_locked+0xf0/0x100
 Call Trace:
 <TASK>
 mt76_dma_cleanup+0x54/0x2f0 [mt76]
 mt7921_pci_remove+0xd5/0x190 [mt7921e]
 pci_device_remove+0x47/0xc0
 device_release_driver_internal+0x19e/0x200
 driver_detach+0x48/0x90
 bus_remove_driver+0x6d/0xf0
 pci_unregister_driver+0x2e/0xb0
 __do_sys_delete_module.isra.0+0x197/0x2e0
 do_syscall_64+0x7b/0x160
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Tested with mt7921e but the same pattern can be actually applied to other
mt76 drivers calling mt76_dma_cleanup() during removal. Tx napi is enabled
in their *_dma_init() functions and only toggled off and on again inside
their suspend/resume/reset paths. So it should be okay to disable tx
napi in such a generic way.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 2ac515a ("mt76: mt76x02: use napi polling for tx cleanup")
Cc: [email protected]
Signed-off-by: Fedor Pchelkin <[email protected]>
Tested-by: Ming Yen Hsieh <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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