linux-toradex.git/sound/core/seq/oss, branch v4.4.95

ALSA: seq: oss: Don't drain at closing a client

2016-03-09T23:34:54+00:00

commit 197b958c1e76a575d77038cc98b4bebc2134279f upstream.

The OSS sequencer client tries to drain the pending events at
releasing.  Unfortunately, as spotted by syzkaller fuzzer, this may
lead to an unkillable process state when the event has been queued at
the far future.  Since the process being released can't be signaled
any longer, it remains and waits for the echo-back event in that far
future.

Back to history, the draining feature was implemented at the time we
misinterpreted POSIX definition for blocking file operation.
Actually, such a behavior is superfluous at release, and we should
just release the device as is instead of keeping it up forever.

This patch just removes the draining call that may block the release
for too long time unexpectedly.

BugLink: http://lkml.kernel.org/r/CACT4Y+Y4kD-aBGj37rf-xBw9bH3GMU6P+MYg4W1e-s-paVD2pg@mail.gmail.com
Reported-by: Dmitry Vyukov 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Degrade the error message for too many opens

2016-02-17T20:30:58+00:00

commit da10816e3d923565b470fec78a674baba794ed33 upstream.

ALSA OSS sequencer spews a kernel error message ("ALSA: seq_oss: too
many applications") when user-space tries to open more than the
limit.  This means that it can easily fill the log buffer.

Since it's merely a normal error, it's safe to suppress it via
pr_debug() instead.

Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix incorrect sanity check at snd_seq_oss_synth_cleanup()

2016-02-17T20:30:58+00:00

commit 599151336638d57b98d92338aa59c048e3a3e97d upstream.

ALSA sequencer OSS emulation code has a sanity check for currently
opened devices, but there is a thinko there, eventually it spews
warnings and skips the operation wrongly like:
  WARNING: CPU: 1 PID: 7573 at sound/core/seq/oss/seq_oss_synth.c:311

Fix this off-by-one error.

Reported-by: Dmitry Vyukov 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq_oss: fix waitqueue_active without memory barrier in snd-seq-oss

2015-10-09T07:45:52+00:00

snd_seq_oss_readq_put_event() seems to be missing a memory barrier which
might cause the waker to not notice the waiter and miss sending a
wake_up as in the following figure.

    snd_seq_oss_readq_put_event		    snd_seq_oss_readq_wait
------------------------------------------------------------------------
					/* wait_event_interruptible_timeout */
					 /* __wait_event_interruptible_timeout */
					  /* ___wait_event */
					  for (;;) {									 prepare_to_wait_event(&wq, &__wait,
					    state);
spin_lock_irqsave(&q->lock, flags);
if (waitqueue_active(&q->midi_sleep))
/* The CPU might reorder the test for
   the waitqueue up here, before
   prior writes complete */
					  if ((q->qlen>0 || q->head==q->tail)
					  ...
					  __ret = schedule_timeout(__ret)
if (q->qlen >= q->maxlen - 1) {
memcpy(&q->q[q->tail], ev, sizeof(*ev));
q->tail = (q->tail + 1) % q->maxlen;
q->qlen++;
------------------------------------------------------------------------

There are two other place in sound/core/seq/oss/ which have similar
code.  The attached patch removes the call to waitqueue_active() leaving
just wake_up() behind.  This fixes the problem because the call to
spin_lock_irqsave() in wake_up() will be an ACQUIRE operation.

I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c  (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).

Signed-off-by: Kosuke Tatsukawa 
Signed-off-by: Takashi Iwai

ALSA: replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS

2015-05-27T19:25:19+00:00

We may disable proc fs only for sound part, to reduce ALSA
memory footprint. So add CONFIG_SND_PROC_FS and replace the
old CONFIG_PROC_FSs in alsa code.

With sound proc fs disabled, we can save about 9KB memory
size on X86_64 platform.

Signed-off-by: Jie Yang 
Reviewed-by: Mark Brown 
Signed-off-by: Takashi Iwai

ALSA: seq_oss: Drop superfluous error/debug messages after malloc failures

2015-03-10T14:39:55+00:00

The kernel memory allocators already report the errors when the
requested allocation fails, thus we don't need to warn it again in
each caller side.

Signed-off-by: Takashi Iwai

ALSA: seq: Drop snd_seq_autoload_lock() and _unlock()

2015-02-12T13:42:31+00:00

The autoload lock became already superfluous due to the recent rework
of autoload code.  Let's drop them now.  This allows us to simplify a
few codes nicely.

Signed-off-by: Takashi Iwai

ALSA: seq: Define driver object in each driver

2015-02-12T13:15:54+00:00

This patch moves the driver object initialization and allocation to
each driver's module init/exit code like other normal drivers.  The
snd_seq_driver struct is now published in seq_device.h, and each
driver is responsible to define it with proper driver attributes
(name, probe and remove) with snd_seq_driver specific attributes as id
and argsize fields.  The helper functions snd_seq_driver_register(),
snd_seq_driver_unregister() and module_snd_seq_driver() are used for
simplifying codes.

Signed-off-by: Takashi Iwai

ALSA: seq: Deletion of unnecessary checks before the function call "snd_midi_event_free"

2015-01-04T14:11:05+00:00

The snd_midi_event_free() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Takashi Iwai

ALSA: core: Deletion of unnecessary checks before two function calls

2014-11-21T19:06:57+00:00

The functions snd_seq_oss_timer_delete() and vunmap() perform also input
parameter validation. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Takashi Iwai