Messages in this thread | | | Date | Mon, 12 Mar 2012 10:35:15 -0400 | From | Dave Jones <> | Subject | snd_pcm lockdep report from 3.3-rc6 |
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I just hit this..
[ INFO: possible recursive locking detected ] 3.3.0-rc6+ #5 Not tainted --------------------------------------------- pulseaudio/1306 is trying to acquire lock: (&(&substream->self_group.lock)->rlock/1){......}, at: [<ffffffffa0468c0b>] snd_pcm_action_group+0x9b/0x260 [snd_pcm]
but task is already holding lock: (&(&substream->self_group.lock)->rlock/1){......}, at: [<ffffffffa0468c0b>] snd_pcm_action_group+0x9b/0x260 [snd_pcm]
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ---- lock(&(&substream->self_group.lock)->rlock/1); lock(&(&substream->self_group.lock)->rlock/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
4 locks held by pulseaudio/1306: #0: (snd_pcm_link_rwlock){......}, at: [<ffffffffa046ab90>] snd_pcm_drop+0x60/0x100 [snd_pcm] #1: (&(&substream->self_group.lock)->rlock){......}, at: [<ffffffffa046ab98>] snd_pcm_drop+0x68/0x100 [snd_pcm] #2: (&(&substream->group->lock)->rlock){......}, at: [<ffffffffa0469ffe>] snd_pcm_action+0x3e/0xb0 [snd_pcm] #3: (&(&substream->self_group.lock)->rlock/1){......}, at: [<ffffffffa0468c0b>] snd_pcm_action_group+0x9b/0x260 [snd_pcm]
stack backtrace: Pid: 1306, comm: pulseaudio Not tainted 3.3.0-rc6+ #5 Call Trace: [<ffffffff810cee87>] __lock_acquire+0xe47/0x1bb0 [<ffffffff810a62b8>] ? sched_clock_cpu+0xb8/0x130 [<ffffffff810d030d>] lock_acquire+0x9d/0x220 [<ffffffffa0468c0b>] ? snd_pcm_action_group+0x9b/0x260 [snd_pcm] [<ffffffff810ca91e>] ? put_lock_stats+0xe/0x40 [<ffffffff8169d3cd>] _raw_spin_lock_nested+0x4d/0x90 [<ffffffffa0468c0b>] ? snd_pcm_action_group+0x9b/0x260 [snd_pcm] [<ffffffffa0468c0b>] snd_pcm_action_group+0x9b/0x260 [snd_pcm] [<ffffffffa046a031>] snd_pcm_action+0x71/0xb0 [snd_pcm] [<ffffffffa046a08a>] snd_pcm_stop+0x1a/0x20 [snd_pcm] [<ffffffffa046abb1>] snd_pcm_drop+0x81/0x100 [snd_pcm] [<ffffffffa046cdf8>] snd_pcm_common_ioctl1+0x678/0xc00 [snd_pcm] [<ffffffffa046d7d7>] snd_pcm_playback_ioctl1+0x147/0x2e0 [snd_pcm] [<ffffffff812c1cbc>] ? file_has_perm+0xdc/0xf0 [<ffffffffa046d9a4>] snd_pcm_playback_ioctl+0x34/0x40 [snd_pcm] [<ffffffff811d2398>] do_vfs_ioctl+0x98/0x570 [<ffffffff811d2901>] sys_ioctl+0x91/0xa0 [<ffffffff816a5de9>] system_call_fastpath+0x16/0x1b
I suspect this ..
static int snd_pcm_action(struct action_ops *ops, struct snd_pcm_substream *substream, int state) { int res;
if (snd_pcm_stream_linked(substream)) { --> if (!spin_trylock(&substream->group->lock)) { spin_unlock(&substream->self_group.lock); spin_lock(&substream->group->lock); spin_lock(&substream->self_group.lock); } res = snd_pcm_action_group(ops, substream, state, 1); spin_unlock(&substream->group->lock); } else { res = snd_pcm_action_single(ops, substream, state); } return res; }
Should that trylock be on self_group.lock ?
Dave
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