linux-kernel - [PATCH 3.12 127/127] ALSA: usb-audio: Fix runtime PM unbalance

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Date:   Fri, 25 Nov 2016 09:30:40 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Takashi Iwai <tiwai@...e.de>,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 127/127] ALSA: usb-audio: Fix runtime PM unbalance

From: Takashi Iwai <tiwai@...e.de>

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

===============

commit 9003ebb13f61e8c78a641e0dda7775183ada0625 upstream.

The fix for deadlock in PM in commit [1ee23fe07ee8: ALSA: usb-audio:
Fix deadlocks at resuming] introduced a new check of in_pm flag.
However, the brainless patch author evaluated it in a wrong way
(logical AND instead of logical OR), thus usb_autopm_get_interface()
is wrongly called at probing, leading to unbalance of runtime PM
refcount.

This patch fixes it by correcting the logic.

Reported-by: Hans Yang <hansy@...dia.com>
Fixes: 1ee23fe07ee8 ('ALSA: usb-audio: Fix deadlocks at resuming')
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 sound/usb/card.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index bc5795f342a7..96a09226be7d 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -661,7 +661,7 @@ int snd_usb_autoresume(struct snd_usb_audio *chip)
 	int err = -ENODEV;
 
 	down_read(&chip->shutdown_rwsem);
-	if (chip->probing && chip->in_pm)
+	if (chip->probing || chip->in_pm)
 		err = 0;
 	else if (!chip->shutdown)
 		err = usb_autopm_get_interface(chip->pm_intf);
-- 
2.10.2