<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/sound, branch v4.16.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ALSA: hda/realtek - adjust the location of one mic</title>
<updated>2018-04-24T07:43:07+00:00</updated>
<author>
<name>Hui Wang</name>
<email>hui.wang@canonical.com</email>
</author>
<published>2018-04-19T05:29:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ab5860f5ce700bc4becc4d6abf01cc380c7ffe85'/>
<id>ab5860f5ce700bc4becc4d6abf01cc380c7ffe85</id>
<content type='text'>
commit a3dafb2200bf3c13905a088e82ae11f1eb275a83 upstream.

There are two front mics on this machine, if we don't adjust the
location for one of them, they will have the same mixer name,
pulseaudio can't handle this situation.

After applying this FIXUP, they will have different mixer name,
then pulseaudio can handle them correctly.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Hui Wang &lt;hui.wang@canonical.com&gt;
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 a3dafb2200bf3c13905a088e82ae11f1eb275a83 upstream.

There are two front mics on this machine, if we don't adjust the
location for one of them, they will have the same mixer name,
pulseaudio can't handle this situation.

After applying this FIXUP, they will have different mixer name,
then pulseaudio can handle them correctly.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Hui Wang &lt;hui.wang@canonical.com&gt;
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: hda/realtek - set PINCFG_HEADSET_MIC to parse_flags</title>
<updated>2018-04-24T07:43:06+00:00</updated>
<author>
<name>Hui Wang</name>
<email>hui.wang@canonical.com</email>
</author>
<published>2018-04-19T05:29:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=667f3e47229683c9af079d7633a8deaddb44623f'/>
<id>667f3e47229683c9af079d7633a8deaddb44623f</id>
<content type='text'>
commit 3ce0d5aa265bcc0a4b281cb0cabf92491276101b upstream.

Otherwise, the pin will be regarded as microphone, and the jack name
is "Mic Phantom", it is always on in the pulseaudio even nothing is
plugged into the jack. So the UI is confusing to users since the
microphone always shows up in the UI even there is no microphone
plugged.

After adding this flag, the jack name is "Headset Mic Phantom", then
the pulseaudio can handle its detection correctly.

Fixes: f0ba9d699e5c ("ALSA: hda/realtek - Fix Dell headset Mic can't record")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Hui Wang &lt;hui.wang@canonical.com&gt;
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 3ce0d5aa265bcc0a4b281cb0cabf92491276101b upstream.

Otherwise, the pin will be regarded as microphone, and the jack name
is "Mic Phantom", it is always on in the pulseaudio even nothing is
plugged into the jack. So the UI is confusing to users since the
microphone always shows up in the UI even there is no microphone
plugged.

After adding this flag, the jack name is "Headset Mic Phantom", then
the pulseaudio can handle its detection correctly.

Fixes: f0ba9d699e5c ("ALSA: hda/realtek - Fix Dell headset Mic can't record")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Hui Wang &lt;hui.wang@canonical.com&gt;
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: hda - New VIA controller suppor no-snoop path</title>
<updated>2018-04-24T07:43:06+00:00</updated>
<author>
<name>David Wang</name>
<email>davidwang@zhaoxin.com</email>
</author>
<published>2018-04-16T09:48:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1798e3019c297751026029a62f09f24c2eff0c5e'/>
<id>1798e3019c297751026029a62f09f24c2eff0c5e</id>
<content type='text'>
commit af52f9982e410edac21ca4b49563053ffc9da1eb upstream.

This patch is used to tell kernel that new VIA HDAC controller also
support no-snoop path.

[ minor coding style fix by tiwai ]

Signed-off-by: David Wang &lt;davidwang@zhaoxin.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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 af52f9982e410edac21ca4b49563053ffc9da1eb upstream.

This patch is used to tell kernel that new VIA HDAC controller also
support no-snoop path.

[ minor coding style fix by tiwai ]

Signed-off-by: David Wang &lt;davidwang@zhaoxin.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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: rawmidi: Fix missing input substream checks in compat ioctls</title>
<updated>2018-04-24T07:43:06+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-04-19T16:16:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=96e48682446474add6afee63e7c06432f5ec7165'/>
<id>96e48682446474add6afee63e7c06432f5ec7165</id>
<content type='text'>
commit 8a56ef4f3ffba9ebf4967b61ef600b0a7ba10f11 upstream.

Some rawmidi compat ioctls lack of the input substream checks
(although they do check only for rfile-&gt;output).  This many eventually
lead to an Oops as NULL substream is passed to the rawmidi core
functions.

Fix it by adding the proper checks before each function call.

The bug was spotted by syzkaller.

Reported-by: syzbot+f7a0348affc3b67bc617@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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 8a56ef4f3ffba9ebf4967b61ef600b0a7ba10f11 upstream.

Some rawmidi compat ioctls lack of the input substream checks
(although they do check only for rfile-&gt;output).  This many eventually
lead to an Oops as NULL substream is passed to the rawmidi core
functions.

Fix it by adding the proper checks before each function call.

The bug was spotted by syzkaller.

Reported-by: syzbot+f7a0348affc3b67bc617@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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: line6: Use correct endpoint type for midi output</title>
<updated>2018-04-24T07:43:06+00:00</updated>
<author>
<name>Fabián Inostroza</name>
<email>soulsonceonfire@gmail.com</email>
</author>
<published>2018-04-12T03:37:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c2795504efef3171260095e13c42452e37066f4e'/>
<id>c2795504efef3171260095e13c42452e37066f4e</id>
<content type='text'>
commit 7ecb46e9ee9af18e304eb9e7d6804c59a408e846 upstream.

Sending MIDI messages to a PODxt through the USB connection shows
"usb_submit_urb failed" in dmesg and the message is not received by
the POD.

The error is caused because in the funcion send_midi_async() in midi.c
there is a call to usb_sndbulkpipe() for endpoint 3 OUT, but the PODxt
USB descriptor shows that this endpoint it's an interrupt endpoint.

Patch tested with PODxt only.

[ The bug has been present from the very beginning in the staging
  driver time, but Fixes below points to the commit moving to sound/
  directory so that the fix can be cleanly applied -- tiwai ]

Fixes: 61864d844c29 ("ALSA: move line6 usb driver into sound/usb")
Signed-off-by: Fabián Inostroza &lt;fabianinostroza@udec.cl&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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 7ecb46e9ee9af18e304eb9e7d6804c59a408e846 upstream.

Sending MIDI messages to a PODxt through the USB connection shows
"usb_submit_urb failed" in dmesg and the message is not received by
the POD.

The error is caused because in the funcion send_midi_async() in midi.c
there is a call to usb_sndbulkpipe() for endpoint 3 OUT, but the PODxt
USB descriptor shows that this endpoint it's an interrupt endpoint.

Patch tested with PODxt only.

[ The bug has been present from the very beginning in the staging
  driver time, but Fixes below points to the commit moving to sound/
  directory so that the fix can be cleanly applied -- tiwai ]

Fixes: 61864d844c29 ("ALSA: move line6 usb driver into sound/usb")
Signed-off-by: Fabián Inostroza &lt;fabianinostroza@udec.cl&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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: Fix endless loop for XRUN recovery in OSS emulation</title>
<updated>2018-04-24T07:43:01+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-04-07T09:48:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=927324e35539a6fef7202346f1dfe03cfbb63e11'/>
<id>927324e35539a6fef7202346f1dfe03cfbb63e11</id>
<content type='text'>
commit e15dc99dbb9cf99f6432e8e3c0b3a8f7a3403a86 upstream.

The commit 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS
ioctls and read/write") split the PCM preparation code to a locked
version, and it added a sanity check of runtime-&gt;oss.prepare flag
along with the change.  This leaded to an endless loop when the stream
gets XRUN: namely, snd_pcm_oss_write3() and co call
snd_pcm_oss_prepare() without setting runtime-&gt;oss.prepare flag and
the loop continues until the PCM state reaches to another one.

As the function is supposed to execute the preparation
unconditionally, drop the invalid state check there.

The bug was triggered by syzkaller.

Fixes: 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS ioctls and read/write")
Reported-by: syzbot+150189c103427d31a053@syzkaller.appspotmail.com
Reported-by: syzbot+7e3f31a52646f939c052@syzkaller.appspotmail.com
Reported-by: syzbot+4f2016cf5185da7759dc@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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 e15dc99dbb9cf99f6432e8e3c0b3a8f7a3403a86 upstream.

The commit 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS
ioctls and read/write") split the PCM preparation code to a locked
version, and it added a sanity check of runtime-&gt;oss.prepare flag
along with the change.  This leaded to an endless loop when the stream
gets XRUN: namely, snd_pcm_oss_write3() and co call
snd_pcm_oss_prepare() without setting runtime-&gt;oss.prepare flag and
the loop continues until the PCM state reaches to another one.

As the function is supposed to execute the preparation
unconditionally, drop the invalid state check there.

The bug was triggered by syzkaller.

Fixes: 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS ioctls and read/write")
Reported-by: syzbot+150189c103427d31a053@syzkaller.appspotmail.com
Reported-by: syzbot+7e3f31a52646f939c052@syzkaller.appspotmail.com
Reported-by: syzbot+4f2016cf5185da7759dc@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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: Fix UAF at PCM release via PCM timer access</title>
<updated>2018-04-24T07:43:01+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-04-02T20:41:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bfb9c474ebfad3851602c7ed6175b7ba651eac62'/>
<id>bfb9c474ebfad3851602c7ed6175b7ba651eac62</id>
<content type='text'>
commit a820ccbe21e8ce8e86c39cd1d3bc8c7d1cbb949b upstream.

The PCM runtime object is created and freed dynamically at PCM stream
open / close time.  This is tracked via substream-&gt;runtime, and it's
cleared at snd_pcm_detach_substream().

The runtime object assignment is protected by PCM open_mutex, so for
all PCM operations, it's safely handled.  However, each PCM substream
provides also an ALSA timer interface, and user-space can access to
this while closing a PCM substream.  This may eventually lead to a
UAF, as snd_pcm_timer_resolution() tries to access the runtime while
clearing it in other side.

Fortunately, it's the only concurrent access from the PCM timer, and
it merely reads runtime-&gt;timer_resolution field.  So, we can avoid the
race by reordering kfree() and wrapping the substream-&gt;runtime
clearance with the corresponding timer lock.

Reported-by: syzbot+8e62ff4e07aa2ce87826@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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 a820ccbe21e8ce8e86c39cd1d3bc8c7d1cbb949b upstream.

The PCM runtime object is created and freed dynamically at PCM stream
open / close time.  This is tracked via substream-&gt;runtime, and it's
cleared at snd_pcm_detach_substream().

The runtime object assignment is protected by PCM open_mutex, so for
all PCM operations, it's safely handled.  However, each PCM substream
provides also an ALSA timer interface, and user-space can access to
this while closing a PCM substream.  This may eventually lead to a
UAF, as snd_pcm_timer_resolution() tries to access the runtime while
clearing it in other side.

Fortunately, it's the only concurrent access from the PCM timer, and
it merely reads runtime-&gt;timer_resolution field.  So, we can avoid the
race by reordering kfree() and wrapping the substream-&gt;runtime
clearance with the corresponding timer lock.

Reported-by: syzbot+8e62ff4e07aa2ce87826@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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: Fix mutex unbalance in OSS emulation ioctls</title>
<updated>2018-04-24T07:43:00+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-03-27T12:32:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ee7294f190c5ef3b4d13800655a96bb28716ddcf'/>
<id>ee7294f190c5ef3b4d13800655a96bb28716ddcf</id>
<content type='text'>
commit f6d297df4dd47ef949540e4a201230d0c5308325 upstream.

The previous fix 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS
ioctls changing busy streams") introduced some mutex unbalance; the
check of runtime-&gt;oss.rw_ref was inserted in a wrong place after the
mutex lock.

This patch fixes the inconsistency by rewriting with the helper
functions to lock/unlock parameters with the stream check.

Fixes: 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams")
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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 f6d297df4dd47ef949540e4a201230d0c5308325 upstream.

The previous fix 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS
ioctls changing busy streams") introduced some mutex unbalance; the
check of runtime-&gt;oss.rw_ref was inserted in a wrong place after the
mutex lock.

This patch fixes the inconsistency by rewriting with the helper
functions to lock/unlock parameters with the stream check.

Fixes: 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams")
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
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: Return -EBUSY for OSS ioctls changing busy streams</title>
<updated>2018-04-24T07:43:00+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-03-23T07:03:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d014fa8f8ae64a641535ed74b59e975935e37211'/>
<id>d014fa8f8ae64a641535ed74b59e975935e37211</id>
<content type='text'>
commit 40cab6e88cb0b6c56d3f30b7491a20e803f948f6 upstream.

OSS PCM stream management isn't modal but it allows ioctls issued at
any time for changing the parameters.  In the previous hardening
patch ("ALSA: pcm: Avoid potential races between OSS ioctls and
read/write"), we covered these races and prevent the corruption by
protecting the concurrent accesses via params_lock mutex.  However,
this means that some ioctls that try to change the stream parameter
(e.g. channels or format) would be blocked until the read/write
finishes, and it may take really long.

Basically changing the parameter while reading/writing is an invalid
operation, hence it's even more user-friendly from the API POV if it
returns -EBUSY in such a situation.

This patch adds such checks in the relevant ioctls with the addition
of read/write access refcount.

Cc: &lt;stable@vger.kernel.org&gt;
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 40cab6e88cb0b6c56d3f30b7491a20e803f948f6 upstream.

OSS PCM stream management isn't modal but it allows ioctls issued at
any time for changing the parameters.  In the previous hardening
patch ("ALSA: pcm: Avoid potential races between OSS ioctls and
read/write"), we covered these races and prevent the corruption by
protecting the concurrent accesses via params_lock mutex.  However,
this means that some ioctls that try to change the stream parameter
(e.g. channels or format) would be blocked until the read/write
finishes, and it may take really long.

Basically changing the parameter while reading/writing is an invalid
operation, hence it's even more user-friendly from the API POV if it
returns -EBUSY in such a situation.

This patch adds such checks in the relevant ioctls with the addition
of read/write access refcount.

Cc: &lt;stable@vger.kernel.org&gt;
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: Avoid potential races between OSS ioctls and read/write</title>
<updated>2018-04-24T07:43:00+00:00</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2018-03-22T17:10:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=337cdfb45e9bbd19a82b0c082c76a627d60ba745'/>
<id>337cdfb45e9bbd19a82b0c082c76a627d60ba745</id>
<content type='text'>
commit 02a5d6925cd34c3b774bdb8eefb057c40a30e870 upstream.

Although we apply the params_lock mutex to the whole read and write
operations as well as snd_pcm_oss_change_params(), we may still face
some races.

First off, the params_lock is taken inside the read and write loop.
This is intentional for avoiding the too long locking, but it allows
the in-between parameter change, which might lead to invalid
pointers.  We check the readiness of the stream and set up via
snd_pcm_oss_make_ready() at the beginning of read and write, but it's
called only once, by assuming that it remains ready in the rest.

Second, many ioctls that may change the actual parameters
(i.e. setting runtime-&gt;oss.params=1) aren't protected, hence they can
be processed in a half-baked state.

This patch is an attempt to plug these holes.  The stream readiness
check is moved inside the read/write inner loop, so that the stream is
always set up in a proper state before further processing.  Also, each
ioctl that may change the parameter is wrapped with the params_lock
for avoiding the races.

The issues were triggered by syzkaller in a few different scenarios,
particularly the one below appearing as GPF in loopback_pos_update.

Reported-by: syzbot+c4227aec125487ec3efa@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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 02a5d6925cd34c3b774bdb8eefb057c40a30e870 upstream.

Although we apply the params_lock mutex to the whole read and write
operations as well as snd_pcm_oss_change_params(), we may still face
some races.

First off, the params_lock is taken inside the read and write loop.
This is intentional for avoiding the too long locking, but it allows
the in-between parameter change, which might lead to invalid
pointers.  We check the readiness of the stream and set up via
snd_pcm_oss_make_ready() at the beginning of read and write, but it's
called only once, by assuming that it remains ready in the rest.

Second, many ioctls that may change the actual parameters
(i.e. setting runtime-&gt;oss.params=1) aren't protected, hence they can
be processed in a half-baked state.

This patch is an attempt to plug these holes.  The stream readiness
check is moved inside the read/write inner loop, so that the stream is
always set up in a proper state before further processing.  Also, each
ioctl that may change the parameter is wrapped with the params_lock
for avoiding the races.

The issues were triggered by syzkaller in a few different scenarios,
particularly the one below appearing as GPF in loopback_pos_update.

Reported-by: syzbot+c4227aec125487ec3efa@syzkaller.appspotmail.com
Cc: &lt;stable@vger.kernel.org&gt;
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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