lkml.org 
[lkml]   [2006]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: workqueue lockdep bug.
Andrew Morton wrote:
> On Mon, 14 Aug 2006 14:33:19 -0400
> Dave Jones <davej@redhat.com> 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


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-08-17 03:13    [W:0.070 / U:2.448 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site