[PATCH 4.4 03/56] ALSA: hda - Fix cancel_work_sync() stall from jackpoll work

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@xxxxxxx>

commit 16037643969e095509cd8446a3f8e406a6dc3a2c upstream.

On AMD/ATI controllers, the HD-audio controller driver allows a bus
reset upon the error recovery, and its procedure includes the
cancellation of pending jack polling work as found in
snd_hda_bus_codec_reset().  This works usually fine, but it becomes a
problem when the reset happens from the jack poll work itself; then
calling cancel_work_sync() from the work being processed tries to wait
the finish endlessly.

As a workaround, this patch adds the check of current_work() and
applies the cancel_work_sync() only when it's not from the
jackpoll_work.

This doesn't fix the root cause of the reported error below, but at
least, it eases the unexpected stall of the whole system.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200937
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Lukas Wunner <lukas@xxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 sound/pci/hda/hda_codec.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -4019,7 +4019,8 @@ void snd_hda_bus_reset_codecs(struct hda
 
 	list_for_each_codec(codec, bus) {
 		/* FIXME: maybe a better way needed for forced reset */
-		cancel_delayed_work_sync(&codec->jackpoll_work);
+		if (current_work() != &codec->jackpoll_work.work)
+			cancel_delayed_work_sync(&codec->jackpoll_work);
 #ifdef CONFIG_PM
 		if (hda_codec_is_power_on(codec)) {
 			hda_call_codec_suspend(codec);