Andrew Morton wrote:
On Mon, 14 Aug 2006 14:33:19 -0400
Dave Jones <[email protected]> wrote:
Andrew,
I merged the workqueue changes from -mm into the Fedora-devel kernel to
kill off those billion cpufreq lockdep warnings. The bug has now mutated
into this:
(Trimmed version of log from
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=202223)
I don't get it.
Let me extend the output a little bit:
clock = mutex_lock(cpu_add_remove_lock)
wqlock = mutex_lock(workqueue_mutex)
slock = mutex_lock(cpu_chain.rwsem)
similar for cunlock, wqunlock, sunlock.
The number after colon is linenumber, where the mutex_XXX lies.
Prints are _after_ mutex_lock and _before_ mutex_unlock calls.
So here it comes:
[ 30.947289] clock: 268
[ 30.947340] Disabling non-boot CPUs ...
[ 30.947392] slock: 334
[ 30.964622] wqlock: 689
[ 30.964659] sunlock: 336
Isn't this strange for validator (lock1-lock2-unlock1 +
(below)lock1-unlock2-unlock1)?
[ 30.966762] Breaking affinity for irq 0
[ 30.968116] CPU 1 is now offline
[ 30.968155] lockdep: not fixing up alternatives.
[ 30.968200]
[ 30.968201] =======================================================
[ 30.968269] [ INFO: possible circular locking dependency detected ]
[ 30.968307] 2.6.18-rc4-mm1-bug #11
[ 30.968342] -------------------------------------------------------
> Breaking affinity for irq 185
> Breaking affinity for irq 193
> Breaking affinity for irq 209
> CPU 1 is now offline
> lockdep: not fixing up alternatives.
>
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.17-1.2548.fc6 #1
> -------------------------------------------------------
> pm-hibernate/4335 is trying to acquire lock:
> ((cpu_chain).rwsem){..--}, at: [<c0430fa4>]
blocking_notifier_call_chain+0x11/0x2d
>
> but task is already holding lock:
> (workqueue_mutex){--..}, at: [<c0612820>] mutex_lock+0x21/0x24
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (workqueue_mutex){--..}:
> [<c043c08e>] lock_acquire+0x4b/0x6d
> [<c06126b1>] __mutex_lock_slowpath+0xbc/0x20a
> [<c0612820>] mutex_lock+0x21/0x24
> [<c0433c25>] workqueue_cpu_callback+0xfd/0x1ee
> [<c0614ef5>] notifier_call_chain+0x20/0x31
> [<c0430fb0>] blocking_notifier_call_chain+0x1d/0x2d
> [<c043f4c5>] _cpu_down+0x47/0x1c4
> [<c043f805>] disable_nonboot_cpus+0x9b/0x11a
> [<c0445b32>] prepare_processes+0xe/0x41
> [<c0445d87>] pm_suspend_disk+0x9/0xf3
> [<c0444e12>] enter_state+0x54/0x1b7
> [<c0444ffb>] state_store+0x86/0x9c
> [<c04a9f88>] subsys_attr_store+0x20/0x25
> [<c04aa08c>] sysfs_write_file+0xab/0xd1
> [<c04732cb>] vfs_write+0xab/0x157
> [<c0473910>] sys_write+0x3b/0x60
> [<c0403faf>] syscall_call+0x7/0xb
cpu_add_remove_lock -> cpu_chain.rwsem -> workqueue_mutex
> -> #0 ((cpu_chain).rwsem){..--}:
> [<c043c08e>] lock_acquire+0x4b/0x6d
> [<c04390a0>] down_read+0x2d/0x40
> [<c0430fa4>] blocking_notifier_call_chain+0x11/0x2d
> [<c043f5aa>] _cpu_down+0x12c/0x1c4
> [<c043f805>] disable_nonboot_cpus+0x9b/0x11a
> [<c0445b32>] prepare_processes+0xe/0x41
> [<c0445d87>] pm_suspend_disk+0x9/0xf3
> [<c0444e12>] enter_state+0x54/0x1b7
> [<c0444ffb>] state_store+0x86/0x9c
> [<c04a9f88>] subsys_attr_store+0x20/0x25
> [<c04aa08c>] sysfs_write_file+0xab/0xd1
> [<c04732cb>] vfs_write+0xab/0x157
> [<c0473910>] sys_write+0x3b/0x60
> [<c0403faf>] syscall_call+0x7/0xb
cpu_add_remove_lock -> cpu_chain.rwsem
> other info that might help us debug this:
>
> 2 locks held by pm-hibernate/4335:
> #0: (cpu_add_remove_lock){--..}, at: [<c0612820>]
mutex_lock+0x21/0x24
> #1: (workqueue_mutex){--..}, at: [<c0612820>] mutex_lock+0x21/0x24
>
> stack backtrace:
> [<c04051ee>] show_trace_log_lvl+0x58/0x159
> [<c04057ea>] show_trace+0xd/0x10
> [<c0405903>] dump_stack+0x19/0x1b
> [<c043b176>] print_circular_bug_tail+0x59/0x64
> [<c043b98e>] __lock_acquire+0x80d/0x99c
> [<c043c08e>] lock_acquire+0x4b/0x6d
> [<c04390a0>] down_read+0x2d/0x40
> [<c0430fa4>] blocking_notifier_call_chain+0x11/0x2d
> [<c043f5aa>] _cpu_down+0x12c/0x1c4
> [<c043f805>] disable_nonboot_cpus+0x9b/0x11a
> [<c0445b32>] prepare_processes+0xe/0x41
> [<c0445d87>] pm_suspend_disk+0x9/0xf3
> [<c0444e12>] enter_state+0x54/0x1b7
> [<c0444ffb>] state_store+0x86/0x9c
> [<c04a9f88>] subsys_attr_store+0x20/0x25
> [<c04aa08c>] sysfs_write_file+0xab/0xd1
> [<c04732cb>] vfs_write+0xab/0x157
> [<c0473910>] sys_write+0x3b/0x60
> [<c0403faf>] syscall_call+0x7/0xb
[ 30.981176] [<c0170514>] sys_write+0x47/0x6e
[ 30.981249] [<c01031fb>] syscall_call+0x7/0xb
[ 30.981322] =======================
[ 30.981378] slock: 334
The one, that failed.
[ 30.981882] wqunlock: 702
[ 30.981939] sunlock: 336
[ 30.981996] CPU1 is down
[ 30.982036] cunlock: 309
[ 30.982075] Stopping tasks: ============
[ 31.149008] ==================|
cpu_add_remove_lock -> cpu_chain.rwsem
I don't see anywhere where this process took workqueue_mutex.
Hope this helps?
regards,
--
http://www.fi.muni.cz/~xslaby/ Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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