Patch "ALSA: hda - Cancel probe work instead of flush at remove" has been added to the 4.4-stable tree

Patch "ALSA: hda - Cancel probe work instead of flush at remove" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ALSA: hda - Cancel probe work instead of flush at remove

to the 4.4-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:
     alsa-hda-cancel-probe-work-instead-of-flush-at-remove.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 0b8c82190c12e530eb6003720dac103bf63e146e Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 15 Feb 2016 16:37:24 +0100
Subject: ALSA: hda - Cancel probe work instead of flush at remove

From: Takashi Iwai <tiwai@suse.de>

commit 0b8c82190c12e530eb6003720dac103bf63e146e upstream.

The commit [991f86d7ae4e: ALSA: hda - Flush the pending probe work at
remove] introduced the sync of async probe work at remove for fixing
the race.  However, this may lead to another hangup when the module
removal is performed quickly before starting the probe work, because
it issues flush_work() and it's blocked forever.

The workaround is to use cancel_work_sync() instead of flush_work()
there.

Fixes: 991f86d7ae4e ('ALSA: hda - Flush the pending probe work at remove')
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/pci/hda/hda_intel.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2143,10 +2143,10 @@ static void azx_remove(struct pci_dev *p
 	struct hda_intel *hda;
 
 	if (card) {
-		/* flush the pending probing work */
+		/* cancel the pending probing work */
 		chip = card->private_data;
 		hda = container_of(chip, struct hda_intel, chip);
-		flush_work(&hda->probe_work);
+		cancel_work_sync(&hda->probe_work);
 
 		snd_card_free(card);
 	}


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-4.4/alsa-seq-fix-leak-of-pool-buffer-at-concurrent-writes.patch
queue-4.4/alsa-pcm-fix-rwsem-deadlock-for-non-atomic-pcm-stream.patch
queue-4.4/alsa-hda-cancel-probe-work-instead-of-flush-at-remove.patch
queue-4.4/alsa-seq-fix-double-port-list-deletion.patch