This is a note to let you know that I've just added the patch titled
media: imon: Fix race getting ictx->lock
to the 4.19-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:
media-imon-fix-race-getting-ictx-lock.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4f5088ef8b41c6edbe0ca7da47152fe97c8780b9
Author: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
Date: Mon May 6 21:10:27 2024 +0000
media: imon: Fix race getting ictx->lock
[ Upstream commit 24147897507cd3a7d63745d1518a638bf4132238 ]
Lets fix a race between mutex_is_lock() and mutex_lock().
<-mutex is not locked
if (!mutex_is_locked(&ictx->lock)) {
unlock = true; <- mutex is locked externaly
mutex_lock(&ictx->lock);
}
Let's use mutex_trylock() that does mutex_is_lock() and mutex_lock()
atomically.
Fix the following cocci warning:
drivers/media/rc/imon.c:1167:1-7: preceding lock on line 1153
Fixes: 23ef710e1a6c ("[media] imon: add conditional locking in change_protocol")
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 99bb7380ee0e5..c78e1a4a10ec5 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -1126,10 +1126,7 @@ static int imon_ir_change_protocol(struct rc_dev *rc, u64 *rc_proto)
memcpy(ictx->usb_tx_buf, &ir_proto_packet, sizeof(ir_proto_packet));
- if (!mutex_is_locked(&ictx->lock)) {
- unlock = true;
- mutex_lock(&ictx->lock);
- }
+ unlock = mutex_trylock(&ictx->lock);
retval = send_packet(ictx);
if (retval)
