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xiaoleiwang123456gregkh
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serial: imx: Use uart_port_lock_irq() instead of uart_port_lock()
When executing 'echo mem > /sys/power/state', the following deadlock occurs. Since there is output during the serial port entering the suspend process, the suspend will be interrupted, resulting in the nesting of locks. Therefore, use uart_port_lock_irq() instead of uart_port_unlock(). WARNING: inconsistent lock state 6.12.0-rc2-00002-g3c199ed5bd64-dirty #23 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. sh/494 [HC0[0]:SC0[0]:HE1:SE1] takes: c4db5850 (&port_lock_key){?.-.}-{3:3}, at: imx_uart_enable_wakeup+0x14/0x254 {IN-HARDIRQ-W} state was registered at: lock_acquire+0x104/0x348 _raw_spin_lock+0x48/0x84 imx_uart_int+0x14/0x4dc __handle_irq_event_percpu+0xac/0x2fc handle_irq_event_percpu+0xc/0x40 handle_irq_event+0x38/0x8c handle_fasteoi_irq+0xb4/0x1b8 handle_irq_desc+0x1c/0x2c gic_handle_irq+0x6c/0xa0 generic_handle_arch_irq+0x2c/0x64 call_with_stack+0x18/0x20 __irq_svc+0x9c/0xbc _raw_spin_unlock_irqrestore+0x2c/0x48 uart_write+0xd8/0x3a0 do_output_char+0x1a8/0x1e4 n_tty_write+0x224/0x440 file_tty_write.constprop.0+0x124/0x250 do_iter_readv_writev+0x100/0x1e0 vfs_writev+0xc4/0x448 do_writev+0x68/0xf8 ret_fast_syscall+0x0/0x1c irq event stamp: 31593 hardirqs last enabled at (31593): [<c1150e48>] _raw_spin_unlock_irqrestore+0x44/0x48 hardirqs last disabled at (31592): [<c07f32f0>] clk_enable_lock+0x60/0x120 softirqs last enabled at (30334): [<c012d1d4>] handle_softirqs+0x2cc/0x478 softirqs last disabled at (30325): [<c012d510>] __irq_exit_rcu+0x120/0x15c other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); <Interrupt> lock(&port_lock_key); Fixes: 3c199ed ("serial: imx: Grab port lock in imx_uart_enable_wakeup()") Signed-off-by: Xiaolei Wang <[email protected]> Reviewed-by: Lucas Stach <[email protected]> Reviewed-by: Fabio Estevam <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
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drivers/tty/serial/imx.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2692,7 +2692,7 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
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{
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u32 ucr3;
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2695-
uart_port_lock(&sport->port);
2695+
uart_port_lock_irq(&sport->port);
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ucr3 = imx_uart_readl(sport, UCR3);
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if (on) {
@@ -2714,7 +2714,7 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
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imx_uart_writel(sport, ucr1, UCR1);
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}
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2717-
uart_port_unlock(&sport->port);
2717+
uart_port_unlock_irq(&sport->port);
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}
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27202720
static int imx_uart_suspend_noirq(struct device *dev)

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