[3.19.y-ckt stable] Patch "ALSA: hda - Flush the pending probe work at remove" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ALSA: hda - Flush the pending probe work at remove

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt14.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 0a1d2dc5175d4fbdb199625b2d87cb53b6eb1156 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai at suse.de>
Date: Wed, 20 Jan 2016 17:19:02 +0100
Subject: ALSA: hda - Flush the pending probe work at remove

commit 991f86d7ae4e1f8c15806e62f97af519e3cdd860 upstream.

As HD-audio driver does deferred probe internally via workqueue, the
driver might go into the mixed state doing both probe and remove when
the module gets unloaded during the probe work.  This eventually
triggers an Oops, unsurprisingly.

For avoiding this race, we just need to flush the pending probe work
explicitly before actually starting the resource release.

Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=960710
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 sound/pci/hda/hda_intel.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 1b6b75f..8751192 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2024,9 +2024,17 @@ out_free:
 static void azx_remove(struct pci_dev *pci)
 {
 	struct snd_card *card = pci_get_drvdata(pci);
+	struct azx *chip;
+	struct hda_intel *hda;
+
+	if (card) {
+		/* flush the pending probing work */
+		chip = card->private_data;
+		hda = container_of(chip, struct hda_intel, chip);
+		flush_work(&hda->probe_work);

-	if (card)
 		snd_card_free(card);
+	}
 }

 /* PCI IDs */
--
1.9.1