From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754638Ab2KNGJa (ORCPT ); Wed, 14 Nov 2012 01:09:30 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54930 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752161Ab2KNFt7 (ORCPT ); Wed, 14 Nov 2012 00:49:59 -0500 Message-Id: <20121114053934.780894499@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Wed, 14 Nov 2012 05:39:40 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Takashi Iwai , Matthieu CASTET Subject: [ 07/82] ALSA: PCM: Fix some races at disconnection In-Reply-To: <20121114053933.726869752@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 9b0573c07f278e9888c352aa9724035c75784ea0 upstream. Fix races at PCM disconnection: - while a PCM device is being opened or closed - while the PCM state is being changed without lock in prepare, hw_params, hw_free ops Reported-by: Matthieu CASTET Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/core/pcm.c | 7 ++++++- sound/core/pcm_native.c | 16 ++++++++++++---- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/sound/core/pcm.c b/sound/core/pcm.c index 8928ca87..86440e4 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -1046,11 +1046,15 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) if (list_empty(&pcm->list)) goto unlock; + mutex_lock(&pcm->open_mutex); list_del_init(&pcm->list); for (cidx = 0; cidx < 2; cidx++) - for (substream = pcm->streams[cidx].substream; substream; substream = substream->next) + for (substream = pcm->streams[cidx].substream; substream; substream = substream->next) { + snd_pcm_stream_lock_irq(substream); if (substream->runtime) substream->runtime->status->state = SNDRV_PCM_STATE_DISCONNECTED; + snd_pcm_stream_unlock_irq(substream); + } list_for_each_entry(notify, &snd_pcm_notify_list, list) { notify->n_disconnect(pcm); } @@ -1066,6 +1070,7 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) } snd_unregister_device(devtype, pcm->card, pcm->device); } + mutex_unlock(&pcm->open_mutex); unlock: mutex_unlock(®ister_mutex); return 0; diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 25ed9fe..e62da93 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -369,6 +369,14 @@ static int period_to_usecs(struct snd_pcm_runtime *runtime) return usecs; } +static void snd_pcm_set_state(struct snd_pcm_substream *substream, int state) +{ + snd_pcm_stream_lock_irq(substream); + if (substream->runtime->status->state != SNDRV_PCM_STATE_DISCONNECTED) + substream->runtime->status->state = state; + snd_pcm_stream_unlock_irq(substream); +} + static int snd_pcm_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params) { @@ -452,7 +460,7 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, runtime->boundary *= 2; snd_pcm_timer_resolution_change(substream); - runtime->status->state = SNDRV_PCM_STATE_SETUP; + snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP); if (pm_qos_request_active(&substream->latency_pm_qos_req)) pm_qos_remove_request(&substream->latency_pm_qos_req); @@ -464,7 +472,7 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, /* hardware might be unusable from this time, so we force application to retry to set the correct hardware parameter settings */ - runtime->status->state = SNDRV_PCM_STATE_OPEN; + snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN); if (substream->ops->hw_free != NULL) substream->ops->hw_free(substream); return err; @@ -512,7 +520,7 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream) return -EBADFD; if (substream->ops->hw_free) result = substream->ops->hw_free(substream); - runtime->status->state = SNDRV_PCM_STATE_OPEN; + snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN); pm_qos_remove_request(&substream->latency_pm_qos_req); return result; } @@ -1320,7 +1328,7 @@ static void snd_pcm_post_prepare(struct snd_pcm_substream *substream, int state) { struct snd_pcm_runtime *runtime = substream->runtime; runtime->control->appl_ptr = runtime->status->hw_ptr; - runtime->status->state = SNDRV_PCM_STATE_PREPARED; + snd_pcm_set_state(substream, SNDRV_PCM_STATE_PREPARED); } static struct action_ops snd_pcm_action_prepare = {