On 22/05/2019 17:41, Pierre-Louis Bossart wrote:
On 5/22/19 11:25 AM, Srinivas Kandagatla wrote:
This patch fixes below warning due to unlocking without locking.
=====================================
WARNING: bad unlock balance detected!
5.1.0-16506-gc1c383a6f0a2-dirty #1523 Tainted: G W
-------------------------------------
aplay/2954 is trying to release lock (&bus->msg_lock) at:
do_bank_switch+0x21c/0x480
but there are no more locks to release!
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
drivers/soundwire/stream.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 544925ff0b40..d16268f30e4f 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -814,7 +814,8 @@ static int do_bank_switch(struct
sdw_stream_runtime *stream)
goto error;
}
- mutex_unlock(&bus->msg_lock);
+ if (mutex_is_locked(&bus->msg_lock))
+ utex_unlock(&bus->msg_lock);
Does this even compile? should be mutex_unlock, no?
We also may want to identify the issue in more details without pushing
it under the rug. The locking mechanism is far from simple and it's
likely there are a number of problems with it.
msg_lock is taken conditionally during multi link bank switch cases,
however the unlock is done unconditionally leading to this warning.
Having a closer look show that there could be a dead lock in this path
while executing sdw_transfer(). And infact there is no need to take
msg_lock in multi link switch cases as sdw_transfer should take care of
this.
Vinod/Sanyog any reason why msg_lock is really required in this path?
--srini
}
return ret;
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