This is a note to let you know that I've just added the patch titled
serial: fix TIOCSRS485 locking
to the 6.3-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:
serial-fix-tiocsrs485-locking.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9e4f2a8004213339e9d837d891a59cc80e082966 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Wed, 12 Apr 2023 14:48:11 +0200
Subject: serial: fix TIOCSRS485 locking
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From: Johan Hovold <johan@xxxxxxxxxx>
commit 9e4f2a8004213339e9d837d891a59cc80e082966 upstream.
The RS485 multipoint addressing support for some reason added a new
ADDRB termios cflag which is (only!) updated from one of the RS485
ioctls.
Make sure to take the termios rw semaphore for the right ioctl (i.e.
set, not get).
Fixes: ae50bb275283 ("serial: take termios_rwsem for ->rs485_config() & pass termios as param")
Cc: stable@xxxxxxxxxxxxxxx # 6.0
Cc: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230412124811.11217-1-johan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1552,7 +1552,7 @@ uart_ioctl(struct tty_struct *tty, unsig
goto out;
/* rs485_config requires more locking than others */
- if (cmd == TIOCGRS485)
+ if (cmd == TIOCSRS485)
down_write(&tty->termios_rwsem);
mutex_lock(&port->mutex);
@@ -1595,7 +1595,7 @@ uart_ioctl(struct tty_struct *tty, unsig
}
out_up:
mutex_unlock(&port->mutex);
- if (cmd == TIOCGRS485)
+ if (cmd == TIOCSRS485)
up_write(&tty->termios_rwsem);
out:
return ret;
Patches currently in stable-queue which might be from johan@xxxxxxxxxx are
queue-6.3/serial-fix-tiocsrs485-locking.patch
