From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933559Ab2JKA07 (ORCPT ); Wed, 10 Oct 2012 20:26:59 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:36598 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933508Ab2JKA0B (ORCPT ); Wed, 10 Oct 2012 20:26:01 -0400 X-Sasl-enc: ZBaHVLuRwFZx2ARyYQKaQKZPbz9Ku+KvTSyNvF5BQgm7 1349915160 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Dylan Reid , Takashi Iwai Subject: [ 109/122] ALSA: hda - Fix hang caused by race during suspend. Date: Thu, 11 Oct 2012 07:54:35 +0900 Message-Id: <20121010225357.626114246@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc0.18.gf84667d In-Reply-To: <20121010225337.989799482@linuxfoundation.org> References: <20121010225337.989799482@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dylan Reid commit d17344b3547669f5b6ee4fda993d03737a141bd6 upstream. There was a race condition when the system suspends while hda_power_work is running in the work queue. If system suspend (snd_hda_suspend) happens after the work queue releases power_lock but before it calls hda_call_codec_suspend, codec_suspend runs with power_on=0, causing the codec to power up for register reads, and hanging when it calls cancel_delayed_work_sync from the running work queue. The call chain from the work queue will look like this: hda_power_work <<- power_on = 1, unlock, then power_on cleard by suspend hda_call_codec_suspend hda_set_power_state snd_hda_codec_read codec_exec_verb snd_hda_power_up snd_hda_power_save __snd_hda_power_up cancel_delayed_work_sync <<-- cancelling executing wq Fix this by waiting for the work queue to finish before starting suspend if suspend is not happening on the work queue. Signed-off-by: Dylan Reid Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/pci/hda/hda_codec.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -3580,7 +3580,7 @@ static inline void hda_exec_init_verbs(s /* * call suspend and power-down; used both from PM and power-save */ -static void hda_call_codec_suspend(struct hda_codec *codec) +static void hda_call_codec_suspend(struct hda_codec *codec, bool in_wq) { if (codec->patch_ops.suspend) codec->patch_ops.suspend(codec); @@ -3589,7 +3589,9 @@ static void hda_call_codec_suspend(struc codec->afg ? codec->afg : codec->mfg, AC_PWRST_D3); #ifdef CONFIG_SND_HDA_POWER_SAVE - cancel_delayed_work(&codec->power_work); + /* Cancel delayed work if we aren't currently running from it. */ + if (!in_wq) + cancel_delayed_work_sync(&codec->power_work); spin_lock(&codec->power_lock); snd_hda_update_power_acct(codec); trace_hda_power_down(codec); @@ -4410,7 +4412,7 @@ static void hda_power_work(struct work_s } spin_unlock(&codec->power_lock); - hda_call_codec_suspend(codec); + hda_call_codec_suspend(codec, true); if (bus->ops.pm_notify) bus->ops.pm_notify(bus); } @@ -5076,7 +5078,7 @@ int snd_hda_suspend(struct hda_bus *bus) list_for_each_entry(codec, &bus->codec_list, list) { if (hda_codec_is_power_on(codec)) - hda_call_codec_suspend(codec); + hda_call_codec_suspend(codec, false); } return 0; }