From: Takashi Iwai Date: Fri, 8 Jul 2016 06:05:19 +0000 (+0200) Subject: ALSA: ctl: Stop notification after disconnection X-Git-Tag: firefly_0821_release~176^2~4^2~37^2~20 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f4ccc29f5bdd41c78ae43c676db809492a7f1ba4;p=firefly-linux-kernel-4.4.55.git ALSA: ctl: Stop notification after disconnection commit f388cdcdd160687c6650833f286b9c89c50960ff upstream. snd_ctl_remove() has a notification for the removal event. It's superfluous when done during the device got disconnected. Although the notification itself is mostly harmless, it may potentially be harmful, and should be suppressed. Actually some components PCM may free ctl elements during the disconnect or free callbacks, thus it's no theoretical issue. This patch adds the check of card->shutdown flag for avoiding unnecessary notifications after (or during) the disconnect. Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- diff --git a/sound/core/control.c b/sound/core/control.c index a85d45595d02..b4fe9b002512 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -160,6 +160,8 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask, if (snd_BUG_ON(!card || !id)) return; + if (card->shutdown) + return; read_lock(&card->ctl_files_rwlock); #if IS_ENABLED(CONFIG_SND_MIXER_OSS) card->mixer_oss_change_count++;