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Message-ID: <48D942B0.7030906@yahoo.com>
Date: Tue, 23 Sep 2008 20:25:36 +0100
From: Sitsofe Wheeler <sitsofe@...oo.com>
To: linux-kernel@...r.kernel.org
Cc: perex@...ex.cz, Ingo Molnar <mingo@...e.hu>
Subject: [lockdep] possible circular locking dependency, between &pcm->open_mutex
and &mm->mmap_sem
Found on linux-tip today. I'm not quite sure what to do with it (what's
the correct procedure for lockdep messages? I didn't turn up much in a
Google search for pcm->open_mutex lockdep ...) and it seems to be ALSA
related...
[ 51.391587] =======================================================
[ 51.391596] [ INFO: possible circular locking dependency detected ]
[ 51.391603] 2.6.27-rc7-tipskw-00756-g6522eab #6
[ 51.391607] -------------------------------------------------------
[ 51.391613] pulseaudio/3736 is trying to acquire lock:
[ 51.391618] (&pcm->open_mutex){--..}, at: [<c032bce8>]
snd_pcm_release+0x58/0xd0
[ 51.391637]
[ 51.391639] but task is already holding lock:
[ 51.391644] (&mm->mmap_sem){----}, at: [<c016fd27>] sys_munmap+0x27/0x50
[ 51.391658]
[ 51.391659] which lock already depends on the new lock.
[ 51.391662]
[ 51.391666]
[ 51.391667] the existing dependency chain (in reverse order) is:
[ 51.391672]
[ 51.391674] -> #2 (&mm->mmap_sem){----}:
[ 51.391683] [<c0148c48>] validate_chain+0xad8/0x1000
[ 51.391693] [<c014a050>] __lock_acquire+0x220/0x5d0
[ 51.391701] [<c014a45c>] lock_acquire+0x5c/0x80
[ 51.391709] [<c016b13b>] might_fault+0x6b/0x90
[ 51.391718] [<c020e7d6>] copy_from_user+0x36/0x70
[ 51.391728] [<c0320f32>] snd_ctl_elem_user_tlv+0x62/0x130
[ 51.391737] [<c03219a0>] snd_ctl_tlv_ioctl+0x120/0x150
[ 51.391745] [<c03223c9>] snd_ctl_ioctl+0x1d9/0xe50
[ 51.391752] [<c0186fad>] vfs_ioctl+0x2d/0x90
[ 51.391760] [<c018706c>] do_vfs_ioctl+0x5c/0x2f0
[ 51.391768] [<c018733e>] sys_ioctl+0x3e/0x60
[ 51.391775] [<c010330d>] sysenter_do_call+0x12/0x35
[ 51.391784] [<ffffffff>] 0xffffffff
[ 51.391791]
[ 51.391792] -> #1 (&card->controls_rwsem){----}:
[ 51.391802] [<c0148c48>] validate_chain+0xad8/0x1000
[ 51.391810] [<c014a050>] __lock_acquire+0x220/0x5d0
[ 51.391818] [<c014a45c>] lock_acquire+0x5c/0x80
[ 51.391825] [<c03caf97>] down_read+0x37/0x50
[ 51.391834] [<c032849c>] snd_pcm_attach_substream+0x7c/0x3c0
[ 51.391843] [<c032bd7b>] snd_pcm_open_substream+0x1b/0xa0
[ 51.391852] [<c032bece>] snd_pcm_open+0xce/0x180
[ 51.391861] [<c032bfd8>] snd_pcm_playback_open+0x28/0x30
[ 51.391869] [<c031e4cb>] snd_open+0x6b/0x80
[ 51.391879] [<c017e040>] chrdev_open+0x70/0x160
[ 51.391888] [<c0179cb4>] __dentry_open+0xf4/0x1f0
[ 51.391896] [<c0179df5>] nameidata_to_filp+0x45/0x60
[ 51.391905] [<c0185a9c>] do_filp_open+0x17c/0x680
[ 51.391915] [<c0179a80>] do_sys_open+0x50/0xe0
[ 51.391923] [<c0179b7e>] sys_open+0x2e/0x40
[ 51.391931] [<c010330d>] sysenter_do_call+0x12/0x35
[ 51.391939] [<ffffffff>] 0xffffffff
[ 51.391951]
[ 51.391952] -> #0 (&pcm->open_mutex){--..}:
[ 51.391961] [<c0148723>] validate_chain+0x5b3/0x1000
[ 51.391969] [<c014a050>] __lock_acquire+0x220/0x5d0
[ 51.391977] [<c014a45c>] lock_acquire+0x5c/0x80
[ 51.391985] [<c03ca9a7>] __mutex_lock_common+0x87/0x360
[ 51.391993] [<c03cacdd>] mutex_lock_nested+0x1d/0x20
[ 51.392001] [<c032bce8>] snd_pcm_release+0x58/0xd0
[ 51.392009] [<c017c8b4>] __fput+0xa4/0x190
[ 51.392012] [<c017c9bd>] fput+0x1d/0x30
[ 51.392012] [<c016e42d>] remove_vma+0x2d/0x50
[ 51.392012] [<c016fa98>] do_munmap+0x198/0x1f0
[ 51.392012] [<c016fd34>] sys_munmap+0x34/0x50
[ 51.392012] [<c010330d>] sysenter_do_call+0x12/0x35
[ 51.392012] [<ffffffff>] 0xffffffff
[ 51.392012]
[ 51.392012] other info that might help us debug this:
[ 51.392012]
[ 51.392012] 1 lock held by pulseaudio/3736:
[ 51.392012] #0: (&mm->mmap_sem){----}, at: [<c016fd27>]
sys_munmap+0x27/0x50
[ 51.392012]
[ 51.392012] stack backtrace:
[ 51.392012] Pid: 3736, comm: pulseaudio Not tainted
2.6.27-rc7-tipskw-00756-g6522eab #6
[ 51.392012] [<c014779b>] print_circular_bug_tail+0x7b/0xd0
[ 51.392012] [<c0146163>] ? print_circular_bug_entry+0x43/0x50
[ 51.392012] [<c0148723>] validate_chain+0x5b3/0x1000
[ 51.392012] [<c014a050>] __lock_acquire+0x220/0x5d0
[ 51.392012] [<c014a45c>] lock_acquire+0x5c/0x80
[ 51.392012] [<c032bce8>] ? snd_pcm_release+0x58/0xd0
[ 51.392012] [<c03ca9a7>] __mutex_lock_common+0x87/0x360
[ 51.392012] [<c032bce8>] ? snd_pcm_release+0x58/0xd0
[ 51.392012] [<c03cacdd>] mutex_lock_nested+0x1d/0x20
[ 51.392012] [<c032bce8>] ? snd_pcm_release+0x58/0xd0
[ 51.392012] [<c032bce8>] snd_pcm_release+0x58/0xd0
[ 51.392012] [<c017c8b4>] __fput+0xa4/0x190
[ 51.392012] [<c017c9bd>] fput+0x1d/0x30
[ 51.392012] [<c016e42d>] remove_vma+0x2d/0x50
[ 51.392012] [<c016fa98>] do_munmap+0x198/0x1f0
[ 51.392012] [<c016fd34>] sys_munmap+0x34/0x50
[ 51.392012] [<c010330d>] sysenter_do_call+0x12/0x35
[ 51.392012] =======================
--
Sitsofe | http://sucs.org/~sits/
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