<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/sound/core, branch v4.14.229</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>ALSA: seq: oss: Fix missing error check in snd_seq_oss_synth_make_info()</title>
<updated>2021-01-30T12:31:12+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2021-01-15T09:34:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1d2b5c1b496d8d9be0ff8ccb4b37e0ccbd943a14'/>
<id>1d2b5c1b496d8d9be0ff8ccb4b37e0ccbd943a14</id>
<content type='text'>
commit 217bfbb8b0bfa24619b11ab75c135fec99b99b20 upstream.

snd_seq_oss_synth_make_info() didn't check the error code from
snd_seq_oss_midi_make_info(), and this leads to the call of strlcpy()
with the uninitialized string as the source, which may lead to the
access over the limit.

Add the proper error check for avoiding the failure.

Reported-by: syzbot+e42504ff21cff05a595f@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20210115093428.15882-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 217bfbb8b0bfa24619b11ab75c135fec99b99b20 upstream.

snd_seq_oss_synth_make_info() didn't check the error code from
snd_seq_oss_midi_make_info(), and this leads to the call of strlcpy()
with the uninitialized string as the source, which may lead to the
access over the limit.

Add the proper error check for avoiding the failure.

Reported-by: syzbot+e42504ff21cff05a595f@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20210115093428.15882-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: pcm: Clear the full allocated memory at hw_params</title>
<updated>2021-01-09T12:37:39+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-12-18T14:56:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=3f8c7a235a524343f2705196bba6c723b3a1fd98'/>
<id>3f8c7a235a524343f2705196bba6c723b3a1fd98</id>
<content type='text'>
[ Upstream commit 618de0f4ef11acd8cf26902e65493d46cc20cc89 ]

The PCM hw_params core function tries to clear up the PCM buffer
before actually using for avoiding the information leak from the
previous usages or the usage before a new allocation.  It performs the
memset() with runtime-&gt;dma_bytes, but this might still leave some
remaining bytes untouched; namely, the PCM buffer size is aligned in
page size for mmap, hence runtime-&gt;dma_bytes doesn't necessarily cover
all PCM buffer pages, and the remaining bytes are exposed via mmap.

This patch changes the memory clearance to cover the all buffer pages
if the stream is supposed to be mmap-ready (that guarantees that the
buffer size is aligned in page size).

Reviewed-by: Lars-Peter Clausen &lt;lars@metafoo.de&gt;
Link: https://lore.kernel.org/r/20201218145625.2045-3-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 618de0f4ef11acd8cf26902e65493d46cc20cc89 ]

The PCM hw_params core function tries to clear up the PCM buffer
before actually using for avoiding the information leak from the
previous usages or the usage before a new allocation.  It performs the
memset() with runtime-&gt;dma_bytes, but this might still leave some
remaining bytes untouched; namely, the PCM buffer size is aligned in
page size for mmap, hence runtime-&gt;dma_bytes doesn't necessarily cover
all PCM buffer pages, and the remaining bytes are exposed via mmap.

This patch changes the memory clearance to cover the all buffer pages
if the stream is supposed to be mmap-ready (that guarantees that the
buffer size is aligned in page size).

Reviewed-by: Lars-Peter Clausen &lt;lars@metafoo.de&gt;
Link: https://lore.kernel.org/r/20201218145625.2045-3-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: seq: Use bool for snd_seq_queue internal flags</title>
<updated>2021-01-09T12:37:38+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-12-06T08:34:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c5eae3edc5273ac59dab70fd49114cce729f27f4'/>
<id>c5eae3edc5273ac59dab70fd49114cce729f27f4</id>
<content type='text'>
commit 4ebd47037027c4beae99680bff3b20fdee5d7c1e upstream.

The snd_seq_queue struct contains various flags in the bit fields.
Those are categorized to two different use cases, both of which are
protected by different spinlocks.  That implies that there are still
potential risks of the bad operations for bit fields by concurrent
accesses.

For addressing the problem, this patch rearranges those flags to be
a standard bool instead of a bit field.

Reported-by: syzbot+63cbe31877bb80ef58f5@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20201206083456.21110-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4ebd47037027c4beae99680bff3b20fdee5d7c1e upstream.

The snd_seq_queue struct contains various flags in the bit fields.
Those are categorized to two different use cases, both of which are
protected by different spinlocks.  That implies that there are still
potential risks of the bad operations for bit fields by concurrent
accesses.

For addressing the problem, this patch rearranges those flags to be
a standard bool instead of a bit field.

Reported-by: syzbot+63cbe31877bb80ef58f5@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20201206083456.21110-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: pcm: oss: Fix a few more UBSAN fixes</title>
<updated>2020-12-29T12:47:05+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-12-18T16:17:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e35c2215b09e2bd72b858cfeeffa40b3570a0860'/>
<id>e35c2215b09e2bd72b858cfeeffa40b3570a0860</id>
<content type='text'>
commit 11cb881bf075cea41092a20236ba708b18e1dbb2 upstream.

There are a few places that call round{up|down}_pow_of_two() with the
value zero, and this causes undefined behavior warnings.  Avoid
calling those macros if such a nonsense value is passed; it's a minor
optimization as well, as we handle it as either an error or a value to
be skipped, instead.

Reported-by: syzbot+33ef0b6639a8d2d42b4c@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20201218161730.26596-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 11cb881bf075cea41092a20236ba708b18e1dbb2 upstream.

There are a few places that call round{up|down}_pow_of_two() with the
value zero, and this causes undefined behavior warnings.  Avoid
calling those macros if such a nonsense value is passed; it's a minor
optimization as well, as we handle it as either an error or a value to
be skipped, instead.

Reported-by: syzbot+33ef0b6639a8d2d42b4c@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20201218161730.26596-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: pcm: oss: Fix potential out-of-bounds shift</title>
<updated>2020-12-29T12:46:46+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-12-09T08:45:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1c25dcb12392b49158b5c9b43f0b6dc2b5cf7567'/>
<id>1c25dcb12392b49158b5c9b43f0b6dc2b5cf7567</id>
<content type='text'>
commit 175b8d89fe292796811fdee87fa39799a5b6b87a upstream.

syzbot spotted a potential out-of-bounds shift in the PCM OSS layer
where it calculates the buffer size with the arbitrary shift value
given via an ioctl.

Add a range check for avoiding the undefined behavior.
As the value can be treated by a signed integer, the max shift should
be 30.

Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20201209084552.17109-2-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 175b8d89fe292796811fdee87fa39799a5b6b87a upstream.

syzbot spotted a potential out-of-bounds shift in the PCM OSS layer
where it calculates the buffer size with the arbitrary shift value
given via an ioctl.

Add a range check for avoiding the undefined behavior.
As the value can be treated by a signed integer, the max shift should
be 30.

Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20201209084552.17109-2-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: ctl: fix error path at adding user-defined element set</title>
<updated>2020-11-24T12:05:51+00:00</updated>
<author>
<name>Takashi Sakamoto</name>
<email>o-takashi@sakamocchi.jp</email>
</author>
<published>2020-11-13T09:20:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e35e86812a7e35c1320fc51c45565f61478dd045'/>
<id>e35e86812a7e35c1320fc51c45565f61478dd045</id>
<content type='text'>
commit 95a793c3bc75cf888e0e641d656e7d080f487d8b upstream.

When processing request to add/replace user-defined element set, check
of given element identifier and decision of numeric identifier is done
in "__snd_ctl_add_replace()" helper function. When the result of check
is wrong, the helper function returns error code. The error code shall
be returned to userspace application.

Current implementation includes bug to return zero to userspace application
regardless of the result. This commit fixes the bug.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: e1a7bfe38079 ("ALSA: control: Fix race between adding and removing a user element")
Signed-off-by: Takashi Sakamoto &lt;o-takashi@sakamocchi.jp&gt;
Link: https://lore.kernel.org/r/20201113092043.16148-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 95a793c3bc75cf888e0e641d656e7d080f487d8b upstream.

When processing request to add/replace user-defined element set, check
of given element identifier and decision of numeric identifier is done
in "__snd_ctl_add_replace()" helper function. When the result of check
is wrong, the helper function returns error code. The error code shall
be returned to userspace application.

Current implementation includes bug to return zero to userspace application
regardless of the result. This commit fixes the bug.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: e1a7bfe38079 ("ALSA: control: Fix race between adding and removing a user element")
Signed-off-by: Takashi Sakamoto &lt;o-takashi@sakamocchi.jp&gt;
Link: https://lore.kernel.org/r/20201113092043.16148-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: seq: oss: Avoid mutex lock for a long-time ioctl</title>
<updated>2020-10-29T08:07:06+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-09-22T08:38:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=00b83a8f598187f5de072b5fe11d01eb4b87c4e5'/>
<id>00b83a8f598187f5de072b5fe11d01eb4b87c4e5</id>
<content type='text'>
[ Upstream commit 2759caad2600d503c3b0ed800e7e03d2cd7a4c05 ]

Recently we applied a fix to cover the whole OSS sequencer ioctls with
the mutex for dealing with the possible races.  This works fine in
general, but in theory, this may lead to unexpectedly long stall if an
ioctl like SNDCTL_SEQ_SYNC is issued and an event with the far future
timestamp was queued.

For fixing such a potential stall, this patch changes the mutex lock
applied conditionally excluding such an ioctl command.  Also, change
the mutex_lock() with the interruptible version for user to allow
escaping from the big-hammer mutex.

Fixes: 80982c7e834e ("ALSA: seq: oss: Serialize ioctls")
Suggested-by: Pavel Machek &lt;pavel@ucw.cz&gt;
Link: https://lore.kernel.org/r/20200922083856.28572-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2759caad2600d503c3b0ed800e7e03d2cd7a4c05 ]

Recently we applied a fix to cover the whole OSS sequencer ioctls with
the mutex for dealing with the possible races.  This works fine in
general, but in theory, this may lead to unexpectedly long stall if an
ioctl like SNDCTL_SEQ_SYNC is issued and an event with the far future
timestamp was queued.

For fixing such a potential stall, this patch changes the mutex lock
applied conditionally excluding such an ioctl command.  Also, change
the mutex_lock() with the interruptible version for user to allow
escaping from the big-hammer mutex.

Fixes: 80982c7e834e ("ALSA: seq: oss: Serialize ioctls")
Suggested-by: Pavel Machek &lt;pavel@ucw.cz&gt;
Link: https://lore.kernel.org/r/20200922083856.28572-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: pcm: oss: Remove superfluous WARN_ON() for mulaw sanity check</title>
<updated>2020-09-09T17:03:11+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-09-01T13:18:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=e463aed86fcec8135b31112a1729b1c03d785a07'/>
<id>e463aed86fcec8135b31112a1729b1c03d785a07</id>
<content type='text'>
commit 949a1ebe8cea7b342085cb6a4946b498306b9493 upstream.

The PCM OSS mulaw plugin has a check of the format of the counter part
whether it's a linear format.  The check is with snd_BUG_ON() that
emits WARN_ON() when the debug config is set, and it confuses
syzkaller as if it were a serious issue.  Let's drop snd_BUG_ON() for
avoiding that.

While we're at it, correct the error code to a more suitable, EINVAL.

Reported-by: syzbot+23b22dc2e0b81cbfcc95@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200901131802.18157-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 949a1ebe8cea7b342085cb6a4946b498306b9493 upstream.

The PCM OSS mulaw plugin has a check of the format of the counter part
whether it's a linear format.  The check is with snd_BUG_ON() that
emits WARN_ON() when the debug config is set, and it confuses
syzkaller as if it were a serious issue.  Let's drop snd_BUG_ON() for
avoiding that.

While we're at it, correct the error code to a more suitable, EINVAL.

Reported-by: syzbot+23b22dc2e0b81cbfcc95@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200901131802.18157-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: seq: oss: Serialize ioctls</title>
<updated>2020-08-21T07:47:57+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-08-04T18:58:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ccafbed8b2f6a9d9298534b39e76da9cb40ff717'/>
<id>ccafbed8b2f6a9d9298534b39e76da9cb40ff717</id>
<content type='text'>
commit 80982c7e834e5d4e325b6ce33757012ecafdf0bb upstream.

Some ioctls via OSS sequencer API may race and lead to UAF when the
port create and delete are performed concurrently, as spotted by a
couple of syzkaller cases.  This patch is an attempt to address it by
serializing the ioctls with the existing register_mutex.

Basically OSS sequencer API is an obsoleted interface and was designed
without much consideration of the concurrency.  There are very few
applications with it, and the concurrent performance isn't asked,
hence this "big hammer" approach should be good enough.

Reported-by: syzbot+1a54a94bd32716796edd@syzkaller.appspotmail.com
Reported-by: syzbot+9d2abfef257f3e2d4713@syzkaller.appspotmail.com
Suggested-by: Hillf Danton &lt;hdanton@sina.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200804185815.2453-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 80982c7e834e5d4e325b6ce33757012ecafdf0bb upstream.

Some ioctls via OSS sequencer API may race and lead to UAF when the
port create and delete are performed concurrently, as spotted by a
couple of syzkaller cases.  This patch is an attempt to address it by
serializing the ioctls with the existing register_mutex.

Basically OSS sequencer API is an obsoleted interface and was designed
without much consideration of the concurrency.  There are very few
applications with it, and the concurrent performance isn't asked,
hence this "big hammer" approach should be good enough.

Reported-by: syzbot+1a54a94bd32716796edd@syzkaller.appspotmail.com
Reported-by: syzbot+9d2abfef257f3e2d4713@syzkaller.appspotmail.com
Suggested-by: Hillf Danton &lt;hdanton@sina.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200804185815.2453-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ALSA: info: Drop WARN_ON() from buffer NULL sanity check</title>
<updated>2020-07-29T05:42:52+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-07-17T08:40:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ac27bfe94f5338c34f185c9bb68d58bfb60caad1'/>
<id>ac27bfe94f5338c34f185c9bb68d58bfb60caad1</id>
<content type='text'>
commit 60379ba08532eca861e933b389526a4dc89e0c42 upstream.

snd_info_get_line() has a sanity check of NULL buffer -- both buffer
itself being NULL and buffer-&gt;buffer being NULL.  Basically both
checks are valid and necessary, but the problem is that it's with
snd_BUG_ON() macro that triggers WARN_ON().  The latter condition
(NULL buffer-&gt;buffer) can be met arbitrarily by user since the buffer
is allocated at the first write, so it means that user can trigger
WARN_ON() at will.

This patch addresses it by simply moving buffer-&gt;buffer NULL check out
of snd_BUG_ON() so that spurious WARNING is no longer triggered.

Reported-by: syzbot+e42d0746c3c3699b6061@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200717084023.5928-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit 60379ba08532eca861e933b389526a4dc89e0c42 upstream.

snd_info_get_line() has a sanity check of NULL buffer -- both buffer
itself being NULL and buffer-&gt;buffer being NULL.  Basically both
checks are valid and necessary, but the problem is that it's with
snd_BUG_ON() macro that triggers WARN_ON().  The latter condition
(NULL buffer-&gt;buffer) can be met arbitrarily by user since the buffer
is allocated at the first write, so it means that user can trigger
WARN_ON() at will.

This patch addresses it by simply moving buffer-&gt;buffer NULL check out
of snd_BUG_ON() so that spurious WARNING is no longer triggered.

Reported-by: syzbot+e42d0746c3c3699b6061@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20200717084023.5928-1-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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