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ALSA: mixart: Fix mutex deadlock 

commit d21b96c8ed upstream.

The code change for switching to non-atomic mode brought the
unexpected mutex deadlock in get_msg().  It converted the spinlock
with the existing mutex, but there were calls with the already holding
the mutex.  Since the only place that needs the extra lock is the code
path from snd_mixart_send_msg(), remove the mutex lock in get_msg()
and apply in the caller side for fixing the mutex deadlock.

Fixes: 8d3a8b5cb5 ("ALSA: mixart: Use nonatomic PCM ops")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201119121440.18945-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Takashi Iwai 2020-11-19 13:14:40 +01:00 committed by Greg Kroah-Hartman
parent b9a69e5d0b
commit c70c1b93f3
1 changed files with 2 additions and 3 deletions
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5
sound/pci/mixart/mixart_core.c
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@ -70,7 +70,6 @@ static int get_msg(struct mixart_mgr *mgr, struct mixart_msg *resp,
unsigned int i;
#endif
mutex_lock(&mgr->msg_lock);
err = 0;
/* copy message descriptor from miXart to driver */
@ -119,8 +118,6 @@ static int get_msg(struct mixart_mgr *mgr, struct mixart_msg *resp,
writel_be(headptr, MIXART_MEM(mgr, MSG_OUTBOUND_FREE_HEAD));
_clean_exit:
mutex_unlock(&mgr->msg_lock);
return err;
}
@ -258,7 +255,9 @@ int snd_mixart_send_msg(struct mixart_mgr *mgr, struct mixart_msg *request, int
resp.data = resp_data;
resp.size = max_resp_size;
mutex_lock(&mgr->msg_lock);
err = get_msg(mgr, &resp, msg_frame);
mutex_unlock(&mgr->msg_lock);
if( request->message_id != resp.message_id )
dev_err(&mgr->pci->dev, "RESPONSE ERROR!\n");