[alsa-devel] 3.18.0-rc1 pulseaudio possible recursive locking

[Takashi Iwai]

At Tue, 21 Oct 2014 00:30:59 +1030,
Arthur Marsh wrote:
> 
> Hi, I have been seeing this a few times lately, and noticed that it was 
> still present
> 
> Is this the right place to report it or should I be reporting a bug 
> against pulseaudio?

This is likely a false-positive report, so ignore it unless you really
encounter the deadlock by this.


Takashi

> 
> 
> [  182.273991] =============================================
> [  182.273996] [ INFO: possible recursive locking detected ]
> [  182.274003] 3.18.0-rc1 #1297 Not tainted
> [  182.274008] ---------------------------------------------
> [  182.274013] pulseaudio/5183 is trying to acquire lock:
> [  182.274018]  (&(&substream->self_group.lock)->rlock/1){......}, at: 
> [<f8432284>] snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274063]
> but task is already holding lock:
> [  182.274069]  (&(&substream->self_group.lock)->rlock/1){......}, at: 
> [<f8432284>] snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274092]
> other info that might help us debug this:
> [  182.274098]  Possible unsafe locking scenario:
> 
> [  182.274104]        CPU0
> [  182.274108]        ----
> [  182.274112]   lock(&(&substream->self_group.lock)->rlock/1);
> [  182.274122]   lock(&(&substream->self_group.lock)->rlock/1);
> [  182.274132]
>   *** DEADLOCK ***
> 
> [  182.274138]  May be due to missing lock nesting notation
> 
> [  182.274146] 4 locks held by pulseaudio/5183:
> [  182.274151]  #0:  (snd_pcm_link_rwlock){......}, at: [<f8432fe3>] 
> snd_pcm_stream_lock+0x1b/0x43 [snd_pcm]
> [  182.274177]  #1:  (&(&substream->self_group.lock)->rlock){......}, 
> at: [<f8432fee>] snd_pcm_stream_lock+0x26/0x43 [snd_pcm]
> [  182.274202]  #2:  (&(&substream->group->lock)->rlock){......}, at: 
> [<f8432cf4>] snd_pcm_action+0x34/0x10b [snd_pcm]
> [  182.274227]  #3:  (&(&substream->self_group.lock)->rlock/1){......}, 
> at: [<f8432284>] snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274254]
> stack backtrace:
> [  182.274263] CPU: 1 PID: 5183 Comm: pulseaudio Not tainted 3.18.0-rc1 
> #1297
> [  182.274269] Hardware name: System Manufacturer System Name/P4S800, 
> BIOS ASUS P4S800 ACPI BIOS Revision 1011 Beta 001 08/30/2005
> [  182.274275]  c1bfc4e0 00000000 e55c9d50 c145d969 c1bfc4e0 e55c9dd4 
> c1082b7b c15b7f9a
> [  182.274295]  e55b630c 0000143f 00000000 e55b6010 e55b6070 00000000 
> 5402a095 00000004
> [  182.274315]  c17a4034 c1bfc4e0 e55b6508 e55b6520 00000000 00000008 
> 00000000 e55b6508
> [  182.274335] Call Trace:
> [  182.274353]  [<c145d969>] dump_stack+0x4b/0x75
> [  182.274366]  [<c1082b7b>] __lock_acquire+0x187c/0x19b3
> [  182.274378]  [<c10834ad>] lock_acquire+0xa1/0x126
> [  182.274394]  [<f8432284>] ? snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274404]  [<c1463a9d>] _raw_spin_lock_nested+0x41/0x4e
> [  182.274420]  [<f8432284>] ? snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274436]  [<f8432284>] snd_pcm_action_group+0x96/0x215 [snd_pcm]
> [  182.274445]  [<c146393b>] ? _raw_spin_trylock+0x6b/0x80
> [  182.274462]  [<f8432d0f>] snd_pcm_action+0x4f/0x10b [snd_pcm]
> [  182.274479]  [<f843332a>] snd_pcm_drop+0x4a/0x7d [snd_pcm]
> [  182.274496]  [<f84351d9>] snd_pcm_common_ioctl1+0x7b0/0xcc4 [snd_pcm]
> [  182.274514]  [<f84357ce>] snd_pcm_playback_ioctl1+0xe1/0x3a8 [snd_pcm]
> [  182.274532]  [<f8435ab7>] snd_pcm_playback_ioctl+0x22/0x35 [snd_pcm]
> [  182.274549]  [<f8435a95>] ? snd_pcm_playback_ioctl1+0x3a8/0x3a8 [snd_pcm]
> [  182.274561]  [<c1171e82>] do_vfs_ioctl+0x306/0x576
> [  182.274573]  [<c117d3ca>] ? mntput_no_expire+0x61/0x1e7
> [  182.274583]  [<c117d377>] ? mntput_no_expire+0xe/0x1e7
> [  182.274594]  [<c117d56b>] ? mntput+0x1b/0x29
> [  182.274603]  [<c1161438>] ? __fput+0x144/0x1aa
> [  182.274614]  [<c1172147>] SyS_ioctl+0x55/0x75
> [  182.274624]  [<c14646e0>] sysenter_do_call+0x12/0x12
> 
> Regards,
> 
> Arthur.
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