[PATCH 6.1 138/440] media: imon: Fix race getting ictx->lock

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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>

[ 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>
---
 drivers/media/rc/imon.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 5719dda6e0f0e..e5590a708f1c5 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -1148,10 +1148,7 @@ 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)
-- 
2.43.0







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