Revert "block, bfq: merge bfq_release_process_ref() into bfq_put_cooperator()"

This reverts commit bc3b1e9.

The bic is associated with sync_bfqq, and bfq_release_process_ref cannot
be put into bfq_put_cooperator.

kasan report:
[  400.347277] ==================================================================
[  400.347287] BUG: KASAN: slab-use-after-free in bic_set_bfqq+0x200/0x230
[  400.347420] Read of size 8 at addr ffff88881cab7d60 by task dockerd/5800
[  400.347430]
[  400.347436] CPU: 24 UID: 0 PID: 5800 Comm: dockerd Kdump: loaded Tainted: G E 6.12.0 #32
[  400.347450] Tainted: [E]=UNSIGNED_MODULE
[  400.347454] Hardware name: VMware, Inc. VMware20,1/440BX Desktop Reference Platform, BIOS VMW201.00V.20192059.B64.2207280713 07/28/2022
[  400.347460] Call Trace:
[  400.347464]  <TASK>
[  400.347468]  dump_stack_lvl+0x5d/0x80
[  400.347490]  print_report+0x174/0x505
[  400.347521]  kasan_report+0xe0/0x160
[  400.347541]  bic_set_bfqq+0x200/0x230
[  400.347549]  bfq_bic_update_cgroup+0x419/0x740
[  400.347560]  bfq_bio_merge+0x133/0x320
[  400.347584]  blk_mq_submit_bio+0x1761/0x1e20
[  400.347625]  __submit_bio+0x28b/0x7b0
[  400.347664]  submit_bio_noacct_nocheck+0x6b2/0xd30
[  400.347690]  iomap_readahead+0x50c/0x680
[  400.347731]  read_pages+0x17f/0x9c0
[  400.347785]  page_cache_ra_unbounded+0x366/0x4a0
[  400.347795]  filemap_fault+0x83d/0x2340
[  400.347819]  __xfs_filemap_fault+0x11a/0x7d0 [xfs]
[  400.349256]  __do_fault+0xf1/0x610
[  400.349270]  do_fault+0x977/0x11a0
[  400.349281]  __handle_mm_fault+0x5d1/0x850
[  400.349314]  handle_mm_fault+0x1f8/0x560
[  400.349324]  do_user_addr_fault+0x324/0x970
[  400.349337]  exc_page_fault+0x76/0xf0
[  400.349350]  asm_exc_page_fault+0x26/0x30
[  400.349360] RIP: 0033:0x55a480d77375
[  400.349384] Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 3b 66 10 0f 86 ae 02 00 00 55 48 89 e5 48 83 ec 58 48 8b 10 <83> 7a 10 00 0f 84 27 02 00 00 44 0f b6 42 28 44 0f b6 4a 29 41 80
[  400.349392] RSP: 002b:00007f18c37fd8b8 EFLAGS: 00010216
[  400.349401] RAX: 00007f18c37fd9d0 RBX: 0000000000000000 RCX: 0000000000000000
[  400.349407] RDX: 000055a484407d38 RSI: 000000c000e8b0c0 RDI: 0000000000000000
[  400.349412] RBP: 00007f18c37fd910 R08: 000055a484017f60 R09: 000055a484066f80
[  400.349417] R10: 0000000000194000 R11: 0000000000000005 R12: 0000000000000008
[  400.349422] R13: 0000000000000000 R14: 000000c000476a80 R15: 0000000000000000
[  400.349430]  </TASK>
[  400.349452]
[  400.349454] Allocated by task 5800:
[  400.349459]  kasan_save_stack+0x30/0x50
[  400.349469]  kasan_save_track+0x14/0x30
[  400.349475]  __kasan_slab_alloc+0x89/0x90
[  400.349482]  kmem_cache_alloc_node_noprof+0xdc/0x2a0
[  400.349492]  bfq_get_queue+0x1ef/0x1100
[  400.349502]  __bfq_get_bfqq_handle_split+0x11a/0x510
[  400.349511]  bfq_insert_requests+0xf55/0x9030
[  400.349519]  blk_mq_flush_plug_list+0x446/0x14c0
[  400.349527]  __blk_flush_plug+0x27c/0x4e0
[  400.349534]  blk_finish_plug+0x52/0xa0
[  400.349540]  _xfs_buf_ioapply+0x739/0xc30 [xfs]
[  400.350246]  __xfs_buf_submit+0x1b2/0x640 [xfs]
[  400.350967]  xfs_buf_read_map+0x306/0xa20 [xfs]
[  400.351672]  xfs_trans_read_buf_map+0x285/0x7d0 [xfs]
[  400.352386]  xfs_imap_to_bp+0x107/0x270 [xfs]
[  400.353077]  xfs_iget+0x70d/0x1eb0 [xfs]
[  400.353786]  xfs_lookup+0x2ca/0x3a0 [xfs]
[  400.354506]  xfs_vn_lookup+0x14e/0x1a0 [xfs]
[  400.355197]  __lookup_slow+0x19c/0x340
[  400.355204]  lookup_one_unlocked+0xfc/0x120
[  400.355211]  ovl_lookup_single+0x1b3/0xcf0 [overlay]
[  400.355255]  ovl_lookup_layer+0x316/0x490 [overlay]
[  400.355295]  ovl_lookup+0x844/0x1fd0 [overlay]
[  400.355351]  lookup_one_qstr_excl+0xef/0x150
[  400.355357]  do_unlinkat+0x22a/0x620
[  400.355366]  __x64_sys_unlinkat+0x109/0x1e0
[  400.355375]  do_syscall_64+0x82/0x160
[  400.355384]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  400.355393]
[  400.355395] Freed by task 5800:
[  400.355400]  kasan_save_stack+0x30/0x50
[  400.355407]  kasan_save_track+0x14/0x30
[  400.355413]  kasan_save_free_info+0x3b/0x70
[  400.355422]  __kasan_slab_free+0x4f/0x70
[  400.355429]  kmem_cache_free+0x176/0x520
[  400.355438]  bfq_put_queue+0x67e/0x980
[  400.355447]  bfq_bic_update_cgroup+0x407/0x740
[  400.355454]  bfq_bio_merge+0x133/0x320
[  400.355460]  blk_mq_submit_bio+0x1761/0x1e20
[  400.355467]  __submit_bio+0x28b/0x7b0
[  400.355473]  submit_bio_noacct_nocheck+0x6b2/0xd30
[  400.355480]  iomap_readahead+0x50c/0x680
[  400.355490]  read_pages+0x17f/0x9c0
[  400.355498]  page_cache_ra_unbounded+0x366/0x4a0
[  400.355505]  filemap_fault+0x83d/0x2340
[  400.355514]  __xfs_filemap_fault+0x11a/0x7d0 [xfs]
[  400.356204]  __do_fault+0xf1/0x610
[  400.356213]  do_fault+0x977/0x11a0
[  400.356221]  __handle_mm_fault+0x5d1/0x850
[  400.356230]  handle_mm_fault+0x1f8/0x560
[  400.356238]  do_user_addr_fault+0x324/0x970
[  400.356248]  exc_page_fault+0x76/0xf0
[  400.356258]  asm_exc_page_fault+0x26/0x30
[  400.356266]
[  400.356269] The buggy address belongs to the object at ffff88881cab7bc0
                which belongs to the cache bfq_queue of size 576
[  400.356276] The buggy address is located 416 bytes inside of
                freed 576-byte region [ffff88881cab7bc0, ffff88881cab7e00)
[  400.356285]
[  400.356287] The buggy address belongs to the physical page:
[  400.356292] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88881cab0b00 pfn:0x81cab0
[  400.356300] head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[  400.356323] flags: 0x50000000000040(head|node=1|zone=2)
[  400.356331] page_type: f5(slab)
[  400.356340] raw: 0050000000000040 ffff88880a00c280 dead000000000122 0000000000000000
[  400.356347] raw: ffff88881cab0b00 00000000802e0025 00000001f5000000 0000000000000000
[  400.356354] head: 0050000000000040 ffff88880a00c280 dead000000000122 0000000000000000
[  400.356359] head: ffff88881cab0b00 00000000802e0025 00000001f5000000 0000000000000000
[  400.356365] head: 0050000000000003 ffffea002072ac01 ffffffffffffffff 0000000000000000
[  400.356370] head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
[  400.356378] page dumped because: kasan: bad access detected
[  400.356381]
[  400.356383] Memory state around the buggy address:
[  400.356387]  ffff88881cab7c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  400.356392]  ffff88881cab7c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  400.356397] >ffff88881cab7d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  400.356400]                                                        ^
[  400.356405]  ffff88881cab7d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  400.356409]  ffff88881cab7e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  400.356413] ==================================================================

Cc: [email protected]
Fixes: bc3b1e9 ("block, bfq: merge bfq_release_process_ref() into bfq_put_cooperator()")
Signed-off-by: Zach Wade <[email protected]>
Cc: Ding Hui <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: zachwade-k

block/bfq-cgroup.c

@@ -736,6 +736,7 @@ static void bfq_sync_bfqq_move(struct bfq_data *bfqd,
 		 */
 		bfq_put_cooperator(sync_bfqq);
 		bic_set_bfqq(bic, NULL, true, act_idx);
+		bfq_release_process_ref(bfqd, sync_bfqq);
 	}
 }
 

block/bfq-iosched.c

@@ -5434,8 +5434,6 @@ void bfq_put_cooperator(struct bfq_queue *bfqq)
 		bfq_put_queue(__bfqq);
 		__bfqq = next;
 	}
-
-	bfq_release_process_ref(bfqq->bfqd, bfqq);
 }
 
 static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
@@ -5448,6 +5446,8 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
 	bfq_log_bfqq(bfqd, bfqq, "exit_bfqq: %p, %d", bfqq, bfqq->ref);
 
 	bfq_put_cooperator(bfqq);
+
+	bfq_release_process_ref(bfqd, bfqq);
 }
 
 static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync,
@@ -6734,6 +6734,8 @@ bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq)
 	bic_set_bfqq(bic, NULL, true, bfqq->actuator_idx);
 
 	bfq_put_cooperator(bfqq);
+
+	bfq_release_process_ref(bfqq->bfqd, bfqq);
 	return NULL;
 }