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* [PATCH] serial: core: Don't drop port_mutex in serial_core_remove_one_port
@ 2023-06-01 10:55 Steven Price
  2023-06-01 10:58 ` Tony Lindgren
  0 siblings, 1 reply; 2+ messages in thread
From: Steven Price @ 2023-06-01 10:55 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jiri Slaby, Tony Lindgren
  Cc: linux-kernel, linux-serial, Andy Shevchenko, linux-omap,
	Vignesh Raghavendra, Sebastian Andrzej Siewior, Johan Hovold,
	John Ogness, Ilpo Järvinen, Dhruva Gole, Steven Price

Commit 84a9582fd203 ("serial: core: Start managing serial controllers to
enable runtime PM") required the caller to hold port_mutex rather than
taking it locally. However the mutex_unlock() call wasn't removed
causing the mutex to be dropped unexpectly. Remove the call to
mutex_unlock() (and fix up the early return) to restore correct
behaviour.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Steven Price <steven.price@arm.com>
---
 drivers/tty/serial/serial_core.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 29bd5ede0b25..efda90215ee9 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3194,7 +3194,7 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 
 	if (!uart_port) {
 		mutex_unlock(&port->mutex);
-		goto out;
+		return;
 	}
 	mutex_unlock(&port->mutex);
 
@@ -3234,8 +3234,6 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 	wait_event(state->remove_wait, !atomic_read(&state->refcount));
 	state->uart_port = NULL;
 	mutex_unlock(&port->mutex);
-out:
-	mutex_unlock(&port_mutex);
 }
 
 /**
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] serial: core: Don't drop port_mutex in serial_core_remove_one_port
  2023-06-01 10:55 [PATCH] serial: core: Don't drop port_mutex in serial_core_remove_one_port Steven Price
@ 2023-06-01 10:58 ` Tony Lindgren
  0 siblings, 0 replies; 2+ messages in thread
From: Tony Lindgren @ 2023-06-01 10:58 UTC (permalink / raw)
  To: Steven Price
  Cc: Greg Kroah-Hartman, Jiri Slaby, linux-kernel, linux-serial,
	Andy Shevchenko, linux-omap, Vignesh Raghavendra,
	Sebastian Andrzej Siewior, Johan Hovold, John Ogness,
	Ilpo Järvinen, Dhruva Gole

* Steven Price <steven.price@arm.com> [230601 10:56]:
> Commit 84a9582fd203 ("serial: core: Start managing serial controllers to
> enable runtime PM") required the caller to hold port_mutex rather than
> taking it locally. However the mutex_unlock() call wasn't removed
> causing the mutex to be dropped unexpectly. Remove the call to
> mutex_unlock() (and fix up the early return) to restore correct
> behaviour.
> 
> Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")

Reviewed-by: Tony Lindgren <tony@atomide.com>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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