From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maciej Rutecki Subject: Re: 3.3-rc2 snd_pcm lockdep backtrace Date: Wed, 8 Feb 2012 18:54:08 +0100 Message-ID: <201202081854.08668.maciej.rutecki@gmail.com> References: <20120206145621.GA4771@zod.bos.redhat.com> Reply-To: maciej.rutecki@gmail.com Mime-Version: 1.0 Content-Type: Text/Plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20120206145621.GA4771@zod.bos.redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Josh Boyer Cc: Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, kernel-team@fedoraproject.org List-Id: alsa-devel@alsa-project.org On poniedzia=C5=82ek, 6 lutego 2012 o 15:56:22 Josh Boyer wrote: > Hi All, >=20 > We've had a report[1] of a lockdep backtrace from the snd_pcm driver.= I > was wondering if anyone had hit this already or had some decent ideas= on > what the issue might be. >=20 > josh >=20 > [1] https://bugzilla.redhat.com/show_bug.cgi?id=3D787319 >=20 > backtrace: > :[ INFO: possible recursive locking detected ] > :3.3.0-0.rc2.git2.1.fc17.x86_64 #1 Not tainted > :--------------------------------------------- > : > :pulseaudio/954 is trying to acquire lock: > : (&(&substream->self_group.lock)->rlock/1){......}, at: > : [] >=20 > snd_pcm_action_group+0xa3/0x240 [snd_pcm] >=20 > :but task is already holding lock: > : (&(&substream->self_group.lock)->rlock/1){......}, at: > : [] >=20 > snd_pcm_action_group+0xa3/0x240 [snd_pcm] >=20 > :other info that might help us debug this: > : Possible unsafe locking scenario: > : CPU0 > : ---- > : =20 > : lock(&(&substream->self_group.lock)->rlock/1); > : lock(&(&substream->self_group.lock)->rlock/1); > :=20 > : *** DEADLOCK *** > : May be due to missing lock nesting notation > : > :4 locks held by pulseaudio/954: > : #0: (snd_pcm_link_rwlock){......}, at: [] >=20 > snd_pcm_drop+0x62/0x110 [snd_pcm] >=20 > : #1: (&(&substream->self_group.lock)->rlock){......}, at: > [] snd_pcm_drop+0x6a/0x110 [snd_pcm] >=20 > : #2: (&(&substream->group->lock)->rlock){......}, at: > : [] >=20 > snd_pcm_action+0x3e/0xb0 [snd_pcm] >=20 > : #3: (&(&substream->self_group.lock)->rlock/1){......}, at: > [] snd_pcm_action_group+0xa3/0x240 [snd_pcm] >=20 > :stack backtrace: > :Pid: 954, comm: pulseaudio Not tainted 3.3.0-0.rc2.git2.1.fc17.x86_6= 4 #1 > : > :Call Trace: > : [] __lock_acquire+0x160c/0x1ad0 > : [] ? __lock_acquire+0x316/0x1ad0 > : [] ? sched_clock+0x9/0x10 > : [] ? sched_clock_local+0x25/0xa0 > : [] lock_acquire+0xa1/0x1e0 > : [] ? snd_pcm_action_group+0xa3/0x240 [snd_pcm] > : [] _raw_spin_lock_nested+0x44/0x80 > : [] ? snd_pcm_action_group+0xa3/0x240 [snd_pcm] > : [] snd_pcm_action_group+0xa3/0x240 [snd_pcm] > : [] snd_pcm_action+0x71/0xb0 [snd_pcm] > : [] snd_pcm_stop+0x1a/0x20 [snd_pcm] > : [] snd_pcm_drop+0x84/0x110 [snd_pcm] > : [] snd_pcm_common_ioctl1+0x4a8/0xbe0 [snd_pcm] > : [] snd_pcm_playback_ioctl1+0x60/0x2d0 [snd_pcm] > : [] ? file_has_perm+0xe1/0xf0 > : [] snd_pcm_playback_ioctl+0x34/0x40 [snd_pcm] > : [] do_vfs_ioctl+0x99/0x5a0 > : [] sys_ioctl+0x99/0xa0 > : [] system_call_fastpath+0x16/0x1b >=20 I created a Bugzilla entry at=20 https://bugzilla.kernel.org/show_bug.cgi?id=3D42746 for your bug report, please add your address to the CC list in there, t= hanks! --=20 Maciej Rutecki http://www.mrutecki.pl