なんぞな
[ 3.139275] ======================================================
[ 3.140019] [ INFO: possible circular locking dependency detected ]
[ 3.140019] 3.2.0-rc1+ #1
[ 3.140019] -------------------------------------------------------
[ 3.140019] udevd/77 is trying to acquire lock:
[ 3.140019] (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff811e6cfd>] lock_trace+0x2d/0x70
[ 3.140019]
[ 3.140019] but task is already holding lock:
[ 3.140019] (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff81190218>] do_lookup+0x2a8/0x3d0
[ 3.140019]
[ 3.140019] which lock already depends on the new lock.
[ 3.140019]
[ 3.140019]
[ 3.140019] the existing dependency chain (in reverse order) is:
[ 3.140019]
[ 3.140019] -> #1 (&sb->s_type->i_mutex_key#7){+.+.+.}:
[ 3.140019] [<ffffffff810a596d>] lock_acquire+0x9d/0x140
[ 3.140019] [<ffffffff8164365f>] mutex_lock_nested+0x3f/0x340
[ 3.140019] [<ffffffff81190218>] do_lookup+0x2a8/0x3d0
[ 3.140019] [<ffffffff81190481>] link_path_walk+0x141/0x8b0
[ 3.140019] [<ffffffff8119294b>] path_openat+0xbb/0x3d0
[ 3.140019] [<ffffffff81192d82>] do_filp_open+0x42/0xa0
[ 3.140019] [<ffffffff811896f2>] open_exec+0x32/0xf0
[ 3.140019] [<ffffffff8118a097>] do_execve_common.isra.29+0x137/0x340
[ 3.140019] [<ffffffff8118a2bb>] do_execve+0x1b/0x20
[ 3.140019] [<ffffffff8101d217>] sys_execve+0x47/0x70
[ 3.140019] [<ffffffff8164eb9c>] stub_execve+0x6c/0xc0
[ 3.140019]
[ 3.140019] -> #0 (&sig->cred_guard_mutex){+.+.+.}:
[ 3.140019] [<ffffffff810a51da>] __lock_acquire+0x1ada/0x1c30
[ 3.140019] [<ffffffff810a596d>] lock_acquire+0x9d/0x140
[ 3.140019] [<ffffffff81643d5f>] mutex_lock_killable_nested+0x3f/0x3d0
[ 3.140019] [<ffffffff811e6cfd>] lock_trace+0x2d/0x70
[ 3.140019] [<ffffffff811e8b16>] proc_lookupfd_common+0x66/0xd0
[ 3.140019] [<ffffffff811e8bb5>] proc_lookupfd+0x15/0x20
[ 3.140019] [<ffffffff8118d975>] d_alloc_and_lookup+0x45/0x90
[ 3.140019] [<ffffffff81190242>] do_lookup+0x2d2/0x3d0
[ 3.140019] [<ffffffff8119123c>] path_lookupat+0x11c/0x760
[ 3.140019] [<ffffffff811918b1>] do_path_lookup+0x31/0xc0
[ 3.140019] [<ffffffff81192cd9>] user_path_at_empty+0x59/0xa0
[ 3.140019] [<ffffffff81192d31>] user_path_at+0x11/0x20
[ 3.140019] [<ffffffff8118766a>] vfs_fstatat+0x3a/0x70
[ 3.140019] [<ffffffff811876db>] vfs_stat+0x1b/0x20
[ 3.140019] [<ffffffff8118781a>] sys_newstat+0x1a/0x40
[ 3.140019] [<ffffffff8164e6c2>] system_call_fastpath+0x16/0x1b
[ 3.140019]
[ 3.140019] other info that might help us debug this:
[ 3.140019]
[ 3.140019] Possible unsafe locking scenario:
[ 3.140019]
[ 3.140019] CPU0 CPU1
[ 3.140019] ---- ----
[ 3.140019] lock(&sb->s_type->i_mutex_key);
[ 3.140019] lock(&sig->cred_guard_mutex);
[ 3.140019] lock(&sb->s_type->i_mutex_key);
[ 3.140019] lock(&sig->cred_guard_mutex);
[ 3.140019]
[ 3.140019] *** DEADLOCK ***
[ 3.140019]
[ 3.140019] 1 lock held by udevd/77:
[ 3.140019] #0: (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff81190218>] do_lookup+0x2a8/0x3d0
[ 3.140019]
[ 3.140019] stack backtrace:
[ 3.140019] Pid: 77, comm: udevd Not tainted 3.2.0-rc1+ #1
[ 3.140019] Call Trace:
[ 3.140019] [<ffffffff8163a483>] print_circular_bug+0x237/0x248
[ 3.140019] [<ffffffff810a51da>] __lock_acquire+0x1ada/0x1c30
[ 3.140019] [<ffffffff8101b8d9>] ? sched_clock+0x9/0x10
[ 3.140019] [<ffffffff81092a25>] ? sched_clock_local+0x25/0x90
[ 3.140019] [<ffffffff8103bc45>] ? pvclock_clocksource_read+0x55/0xf0
[ 3.140019] [<ffffffff810a596d>] lock_acquire+0x9d/0x140
[ 3.140019] [<ffffffff811e6cfd>] ? lock_trace+0x2d/0x70
[ 3.140019] [<ffffffff81092a25>] ? sched_clock_local+0x25/0x90
[ 3.140019] [<ffffffff811eaa30>] ? proc_fdinfo_instantiate+0xa0/0xa0
[ 3.140019] [<ffffffff81643d5f>] mutex_lock_killable_nested+0x3f/0x3d0
[ 3.140019] [<ffffffff811e6cfd>] ? lock_trace+0x2d/0x70
[ 3.140019] [<ffffffff810a089c>] ? lock_release_holdtime.part.25+0x1c/0x190
[ 3.140019] [<ffffffff811e6cfd>] ? lock_trace+0x2d/0x70
[ 3.140019] [<ffffffff811eaa30>] ? proc_fdinfo_instantiate+0xa0/0xa0
[ 3.140019] [<ffffffff811e6cfd>] lock_trace+0x2d/0x70
[ 3.140019] [<ffffffff811e8b16>] proc_lookupfd_common+0x66/0xd0
[ 3.140019] [<ffffffff811e8bb5>] proc_lookupfd+0x15/0x20
[ 3.140019] [<ffffffff8118d975>] d_alloc_and_lookup+0x45/0x90
[ 3.140019] [<ffffffff8119bfd5>] ? d_lookup+0x35/0x60
[ 3.140019] [<ffffffff81190242>] do_lookup+0x2d2/0x3d0
[ 3.140019] [<ffffffff8119123c>] path_lookupat+0x11c/0x760
[ 3.140019] [<ffffffff811446b0>] ? might_fault+0x40/0x90
[ 3.140019] [<ffffffff81339647>] ? __strncpy_from_user+0x27/0x60
[ 3.140019] [<ffffffff811918b1>] do_path_lookup+0x31/0xc0
[ 3.140019] [<ffffffff81192cd9>] user_path_at_empty+0x59/0xa0
[ 3.140019] [<ffffffff811a15e0>] ? vfsmount_lock_local_unlock_cpu+0x50/0x50
[ 3.140019] [<ffffffff81092bb8>] ? sched_clock_cpu+0xa8/0x110
[ 3.140019] [<ffffffff8109ff8d>] ? trace_hardirqs_off+0xd/0x10
[ 3.140019] [<ffffffff81092c8f>] ? local_clock+0x6f/0x80
[ 3.140019] [<ffffffff810a089c>] ? lock_release_holdtime.part.25+0x1c/0x190
[ 3.140019] [<ffffffff81192d31>] user_path_at+0x11/0x20
[ 3.140019] [<ffffffff8118766a>] vfs_fstatat+0x3a/0x70
[ 3.140019] [<ffffffff8118e0b3>] ? putname+0x33/0x50
[ 3.140019] [<ffffffff810a6435>] ? trace_hardirqs_on_caller+0x105/0x190
[ 3.140019] [<ffffffff811876db>] vfs_stat+0x1b/0x20
[ 3.140019] [<ffffffff8118781a>] sys_newstat+0x1a/0x40
[ 3.140019] [<ffffffff810a6435>] ? trace_hardirqs_on_caller+0x105/0x190
[ 3.140019] [<ffffffff8133925e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 3.140019] [<ffffffff8164e6c2>] system_call_fastpath+0x16/0x1b
[ 3.430319] udevd[78]: starting version 173リリース前バージョンなんか開発に使うからこうなる。。。
