From fe0ebeafc3b723b2f8edf27ecec6d353b08397df Mon Sep 17 00:00:00 2001 From: Qiu-ji Chen Date: Thu, 7 Nov 2024 19:33:37 +0800 Subject: [PATCH] staging: greybus: uart: Fix atomicity violation in get_serial_info() 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 Fixes: 0aad5ad563c8 ("greybus/uart: switch to ->[sg]et_serial()") Reviewed-by: Johan Hovold Reviewed-by: Dan Carpenter Reviewed-by: Alex Elder Link: https://lore.kernel.org/r/20241107113337.402042-1-chenqiuji666@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/uart.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c index cdf4ebb93b10..8eab94cb06fa 100644 --- a/drivers/staging/greybus/uart.c +++ b/drivers/staging/greybus/uart.c @@ -596,11 +596,13 @@ 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; }