Uh? That's kernel output, right? So how could PA be at fault here? Reassigning to the kernel.

Created attachment 356173 [details]
kernel messages (dmesg)

Same issue with kernel-2.6.31-0.118.rc5.fc12.x86_64. Note that I'm not aware of any PulseAudio clients, I usually listen to the music with Audacious and ALSA backend directly.

Still happens with kernel-2.6.31-0.185.rc7.git6.fc12.x86_64.

=============================================
[ INFO: possible recursive locking detected ]
2.6.31-0.203.rc8.git2.fc12.x86_64 #1
---------------------------------------------
pulseaudio/2107 is trying to acquire lock:
 (&substream->self_group.lock/1){......}, at: [<ffffffffa0213085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]

but task is already holding lock:
 (&substream->self_group.lock/1){......}, at: [<ffffffffa0213085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]

other info that might help us debug this:
4 locks held by pulseaudio/2107:
 #0:  (snd_pcm_link_rwlock){......}, at: [<ffffffffa0211e31>] snd_pcm_stream_lock_irq+0x2c/0x53 [snd_pcm]
 #1:  (&substream->self_group.lock){......}, at: [<ffffffffa0211e3d>] snd_pcm_stream_lock_irq+0x38/0x53 [snd_pcm]
 #2:  (&substream->group->lock){......}, at: [<ffffffffa0213401>] snd_pcm_action+0x42/0xb3 [snd_pcm]
 #3:  (&substream->self_group.lock/1){......}, at: [<ffffffffa0213085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]

stack backtrace:
Pid: 2107, comm: pulseaudio Not tainted 2.6.31-0.203.rc8.git2.fc12.x86_64 #1
Call Trace:
 [<ffffffff8109783b>] __lock_acquire+0xb84/0xc0e
 [<ffffffff810979b3>] lock_acquire+0xee/0x12e
 [<ffffffffa0213085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
 [<ffffffffa0213085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
 [<ffffffffa0213085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
 [<ffffffff81505ca1>] _spin_lock_nested+0x43/0x8c
 [<ffffffffa0213085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
 [<ffffffffa0213401>] ? snd_pcm_action+0x42/0xb3 [snd_pcm]
 [<ffffffffa0213085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]
 [<ffffffffa0213401>] ? snd_pcm_action+0x42/0xb3 [snd_pcm]
 [<ffffffffa0213437>] snd_pcm_action+0x78/0xb3 [snd_pcm]
 [<ffffffffa0211e3d>] ? snd_pcm_stream_lock_irq+0x38/0x53 [snd_pcm]
 [<ffffffffa021349f>] snd_pcm_stop+0x2d/0x43 [snd_pcm]
 [<ffffffffa0213558>] snd_pcm_drop+0xa3/0xcf [snd_pcm]
 [<ffffffffa0216789>] snd_pcm_common_ioctl1+0xb7a/0xc40 [snd_pcm]
 [<ffffffff8122d8da>] ? __rcu_read_unlock+0x34/0x4a
 [<ffffffff8122e884>] ? avc_has_perm_noaudit+0x3c9/0x3ef
 [<ffffffff81095afb>] ? mark_lock+0x3c/0x253
 [<ffffffffa0216da2>] snd_pcm_playback_ioctl1+0x264/0x295 [snd_pcm]
 [<ffffffffa02177a2>] snd_pcm_playback_ioctl+0x42/0x5a [snd_pcm]
 [<ffffffff8115183f>] vfs_ioctl+0x31/0xaa
 [<ffffffff81151e01>] do_vfs_ioctl+0x4aa/0x506
 [<ffffffff81151ec2>] sys_ioctl+0x65/0x9c
 [<ffffffff81011f42>] system_call_fastpath+0x16/0x1b

Oct 6 23:44:37 kernel: =============================================
Oct 6 23:44:37 kernel: [ INFO: possible recursive locking detected ]
Oct 6 23:44:37 kernel: 2.6.31.1-56.fc12.x86_64 #1
Oct 6 23:44:37 kernel: ---------------------------------------------
Oct 6 23:44:37 kernel: pulseaudio/2059 is trying to acquire lock:
Oct 6 23:44:37 kernel: (&substream->self_group.lock/1){......}, at: [<ffffffffa0181085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel:
Oct 6 23:44:37 kernel: but task is already holding lock:
Oct 6 23:44:37 kernel: (&substream->self_group.lock/1){......}, at: [<ffffffffa0181085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel:
Oct 6 23:44:37 kernel: other info that might help us debug this:
Oct 6 23:44:37 kernel: 4 locks held by pulseaudio/2059:
Oct 6 23:44:37 kernel: #0: (snd_pcm_link_rwlock){......}, at: [<ffffffffa017fe31>] snd_pcm_stream_lock_irq+0x2c/0x53 [snd_pcm]
Oct 6 23:44:37 kernel: #1: (&substream->self_group.lock){......}, at: [<ffffffffa017fe3d>] snd_pcm_stream_lock_irq+0x38/0x53 [snd_pcm]
Oct 6 23:44:37 kernel: #2: (&substream->group->lock){......}, at: [<ffffffffa0181401>] snd_pcm_action+0x42/0xb3 [snd_pcm]
Oct 6 23:44:37 kernel: #3: (&substream->self_group.lock/1){......}, at: [<ffffffffa0181085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel:
Oct 6 23:44:37 kernel: stack backtrace:
Oct 6 23:44:37 kernel: Pid: 2059, comm: pulseaudio Not tainted 2.6.31.1-56.fc12.x86_64 #1
Oct 6 23:44:37 kernel: Call Trace:
Oct 6 23:44:37 kernel: [<ffffffff810978db>] __lock_acquire+0xb84/0xc0e
Oct 6 23:44:37 kernel: [<ffffffff81097a53>] lock_acquire+0xee/0x12e
Oct 6 23:44:37 kernel: [<ffffffffa0181085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffff815066f9>] _spin_lock_nested+0x43/0x8c
Oct 6 23:44:37 kernel: [<ffffffffa0181085>] ? snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181401>] ? snd_pcm_action+0x42/0xb3 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181085>] snd_pcm_action_group+0x62/0x23a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181401>] ? snd_pcm_action+0x42/0xb3 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181437>] snd_pcm_action+0x78/0xb3 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa017fe3d>] ? snd_pcm_stream_lock_irq+0x38/0x53 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa018149f>] snd_pcm_stop+0x2d/0x43 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0181558>] snd_pcm_drop+0xa3/0xcf [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa0184789>] snd_pcm_common_ioctl1+0xb7a/0xc40 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffff8122db36>] ? __rcu_read_unlock+0x34/0x4a
Oct 6 23:44:37 kernel: [<ffffffff8122eae0>] ? avc_has_perm_noaudit+0x3c9/0x3ef
Oct 6 23:44:37 kernel: [<ffffffff81095b9b>] ? mark_lock+0x3c/0x253
Oct 6 23:44:37 kernel: [<ffffffffa0184da2>] snd_pcm_playback_ioctl1+0x264/0x295 [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffffa01857a2>] snd_pcm_playback_ioctl+0x42/0x5a [snd_pcm]
Oct 6 23:44:37 kernel: [<ffffffff81151a13>] vfs_ioctl+0x31/0xaa
Oct 6 23:44:37 kernel: [<ffffffff81151fd5>] do_vfs_ioctl+0x4aa/0x506
Oct 6 23:44:37 kernel: [<ffffffff81152096>] sys_ioctl+0x65/0x9c
Oct 6 23:44:37 kernel: [<ffffffff81011f42>] system_call_fastpath+0x16/0x1b

This bug appears to have been reported against 'rawhide' during the Fedora 13 development cycle.
Changing version to '13'.

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