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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Takashi Iwai <tiwai@suse.de>, Sasha Levin <sashal@kernel.org>,
	alsa-devel@alsa-project.org, paulhsia <paulhsia@chromium.org>
Subject: [alsa-devel] [PATCH AUTOSEL 4.4 4/9] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed()
Date: Fri, 22 Nov 2019 14:50:09 -0500	[thread overview]
Message-ID: <20191122195014.25065-4-sashal@kernel.org> (raw)
In-Reply-To: <20191122195014.25065-1-sashal@kernel.org>

From: paulhsia <paulhsia@chromium.org>

[ Upstream commit f5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439 ]

If the nullity check for `substream->runtime` is outside of the lock
region, it is possible to have a null runtime in the critical section
if snd_pcm_detach_substream is called right before the lock.

Signed-off-by: paulhsia <paulhsia@chromium.org>
Link: https://lore.kernel.org/r/20191112171715.128727-2-paulhsia@chromium.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/core/pcm_lib.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 3ce2b87717623..950730709d28a 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1877,11 +1877,14 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 	struct snd_pcm_runtime *runtime;
 	unsigned long flags;
 
-	if (PCM_RUNTIME_CHECK(substream))
+	if (snd_BUG_ON(!substream))
 		return;
-	runtime = substream->runtime;
 
 	snd_pcm_stream_lock_irqsave(substream, flags);
+	if (PCM_RUNTIME_CHECK(substream))
+		goto _unlock;
+	runtime = substream->runtime;
+
 	if (!snd_pcm_running(substream) ||
 	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
 		goto _end;
@@ -1892,6 +1895,7 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 #endif
  _end:
 	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
+ _unlock:
 	snd_pcm_stream_unlock_irqrestore(substream, flags);
 }
 
-- 
2.20.1

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Alsa-devel@alsa-project.org
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WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: paulhsia <paulhsia@chromium.org>, Takashi Iwai <tiwai@suse.de>,
	Sasha Levin <sashal@kernel.org>,
	alsa-devel@alsa-project.org
Subject: [PATCH AUTOSEL 4.4 4/9] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed()
Date: Fri, 22 Nov 2019 14:50:09 -0500	[thread overview]
Message-ID: <20191122195014.25065-4-sashal@kernel.org> (raw)
In-Reply-To: <20191122195014.25065-1-sashal@kernel.org>

From: paulhsia <paulhsia@chromium.org>

[ Upstream commit f5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439 ]

If the nullity check for `substream->runtime` is outside of the lock
region, it is possible to have a null runtime in the critical section
if snd_pcm_detach_substream is called right before the lock.

Signed-off-by: paulhsia <paulhsia@chromium.org>
Link: https://lore.kernel.org/r/20191112171715.128727-2-paulhsia@chromium.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/core/pcm_lib.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 3ce2b87717623..950730709d28a 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1877,11 +1877,14 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 	struct snd_pcm_runtime *runtime;
 	unsigned long flags;
 
-	if (PCM_RUNTIME_CHECK(substream))
+	if (snd_BUG_ON(!substream))
 		return;
-	runtime = substream->runtime;
 
 	snd_pcm_stream_lock_irqsave(substream, flags);
+	if (PCM_RUNTIME_CHECK(substream))
+		goto _unlock;
+	runtime = substream->runtime;
+
 	if (!snd_pcm_running(substream) ||
 	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
 		goto _end;
@@ -1892,6 +1895,7 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 #endif
  _end:
 	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
+ _unlock:
 	snd_pcm_stream_unlock_irqrestore(substream, flags);
 }
 
-- 
2.20.1


  parent reply	other threads:[~2019-11-22 19:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-22 19:50 [PATCH AUTOSEL 4.4 1/9] autofs: fix a leak in autofs_expire_indirect() Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 2/9] NFC: nxp-nci: Fix NULL pointer dereference after I2C communication error Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 3/9] Input: cyttsp4_core - fix use after free bug Sasha Levin
2019-11-22 19:50 ` Sasha Levin [this message]
2019-11-22 19:50   ` [PATCH AUTOSEL 4.4 4/9] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed() Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 5/9] slip: Fix memory leak in slip_open error path Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 6/9] net: cdc_ncm: Signedness bug in cdc_ncm_set_dgram_size() Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 7/9] slcan: Fix memory leak in error path Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 8/9] rsxx: add missed destroy_workqueue calls in remove Sasha Levin
2019-11-22 19:50 ` [PATCH AUTOSEL 4.4 9/9] net: ep93xx_eth: fix mismatch of request_mem_region " Sasha Levin

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