Commit 919c5184 authored Nov 19, 2020 by Takashi Iwai Committed by Greg Kroah-Hartman Nov 24, 2020

ALSA: mixart: Fix mutex deadlock



commit d21b96c8ed2aea7e6b7bf4735e1d2503cfbf4072 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: 8d3a8b5c ("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>

parent f72cedf7

sound/pci/mixart/mixart_core.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -83,7 +83,6 @@ 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 */
		@@ -132,8 +131,6 @@ 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;
		}

		@@ -271,7 +268,9 @@ 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");