diff options
| author | Michał Mirosław <mirq-linux@rere.qmqm.pl> | 2020-06-08 12:06:32 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-06-08 15:01:45 +0200 |
| commit | e18035cf5cb3d2bf8e4f4d350a23608bd208b934 (patch) | |
| tree | 447725e4df87724f1224303c774ca29e94ad8b76 /sound/core | |
| parent | e4b0e41fee948ad327f9c912160aa4b50a6a4340 (diff) | |
ALSA: pcm: fix snd_pcm_link() lockdep splat
Add and use snd_pcm_stream_lock_nested() in snd_pcm_link/unlink
implementation. The code is fine, but generates a lockdep complaint:
============================================
WARNING: possible recursive locking detected
5.7.1mq+ #381 Tainted: G O
--------------------------------------------
pulseaudio/4180 is trying to acquire lock:
ffff888402d6f508 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xda8/0xee0 [snd_pcm]
but task is already holding lock:
ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&group->lock);
lock(&group->lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by pulseaudio/4180:
#0: ffffffffa1a05190 (snd_pcm_link_rwsem){++++}-{3:3}, at: snd_pcm_common_ioctl+0xca0/0xee0 [snd_pcm]
#1: ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm]
[...]
Cc: stable@vger.kernel.org
Fixes: f57f3df03a8e ("ALSA: pcm: More fine-grained PCM link locking")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/37252c65941e58473b1219ca9fab03d48f47e3e3.1591610330.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/pcm_native.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index aef860256278..c08732998a42 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -138,6 +138,16 @@ void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream) } EXPORT_SYMBOL_GPL(snd_pcm_stream_lock_irq); +static void snd_pcm_stream_lock_nested(struct snd_pcm_substream *substream) +{ + struct snd_pcm_group *group = &substream->self_group; + + if (substream->pcm->nonatomic) + mutex_lock_nested(&group->mutex, SINGLE_DEPTH_NESTING); + else + spin_lock_nested(&group->lock, SINGLE_DEPTH_NESTING); +} + /** * snd_pcm_stream_unlock_irq - Unlock the PCM stream * @substream: PCM substream @@ -2194,7 +2204,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) snd_pcm_stream_unlock_irq(substream); snd_pcm_group_lock_irq(target_group, nonatomic); - snd_pcm_stream_lock(substream1); + snd_pcm_stream_lock_nested(substream1); snd_pcm_group_assign(substream1, target_group); refcount_inc(&target_group->refs); snd_pcm_stream_unlock(substream1); @@ -2210,7 +2220,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) static void relink_to_local(struct snd_pcm_substream *substream) { - snd_pcm_stream_lock(substream); + snd_pcm_stream_lock_nested(substream); snd_pcm_group_assign(substream, &substream->self_group); snd_pcm_stream_unlock(substream); } |