This is a note to let you know that I've just added the patch titled
staging: greybus: uart: Fix atomicity violation in get_serial_info()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
staging-greybus-uart-fix-atomicity-violation-in-get_.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit be8fa963ec0b0e359b07ab763a7a10f460e2ddde
Author: Qiu-ji Chen <chenqiuji666@xxxxxxxxx>
Date: Thu Nov 7 19:33:37 2024 +0800
staging: greybus: uart: Fix atomicity violation in get_serial_info()
[ Upstream commit fe0ebeafc3b723b2f8edf27ecec6d353b08397df ]
Our static checker found a bug where set_serial_info() uses a mutex, but
get_serial_info() does not. Fortunately, the impact of this is relatively
minor. It doesn't cause a crash or any other serious issues. However, if a
race condition occurs between set_serial_info() and get_serial_info(),
there is a chance that the data returned by get_serial_info() will be
meaningless.
Signed-off-by: Qiu-ji Chen <chenqiuji666@xxxxxxxxx>
Fixes: 0aad5ad563c8 ("greybus/uart: switch to ->[sg]et_serial()")
Reviewed-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Alex Elder <elder@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20241107113337.402042-1-chenqiuji666@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index dc4ed0ff1ae27..b6b136d6a691d 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -597,11 +597,13 @@ static int get_serial_info(struct tty_struct *tty,
struct gb_tty *gb_tty = tty->driver_data;
ss->line = gb_tty->minor;
+ mutex_lock(&gb_tty->port.mutex);
ss->close_delay = jiffies_to_msecs(gb_tty->port.close_delay) / 10;
ss->closing_wait =
gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE :
jiffies_to_msecs(gb_tty->port.closing_wait) / 10;
+ mutex_unlock(&gb_tty->port.mutex);
return 0;
}
