Hi,

Ingo Molnar schrieb:
> 
> So you did get stacktraces? You might want to boot with 
> CONFIG_PROVE_LOCKING=y, that could also catch and report the lockup 
> scenario.

This is what I have got:

[   12.340122] =============================================

[   12.341044] [ INFO: possible recursive locking detected ]

[   12.341044] 2.6.29-rc1-00041-gacd1e11 #143

[   12.341044] ---------------------------------------------

[   12.341044] events/0/9 is trying to acquire lock:

[   12.341044]  (events){--..}, at: [<ffffffff80254783>]
flush_work+0x33/0x100
[   12.341044]

[   12.341044] but task is already holding lock:

[   12.341044]  (events){--..}, at: [<ffffffff80253ef7>]
run_workqueue+0x107/0x230

[   12.341044]

[   12.341044] other info that might help us debug this:

[   12.341044] 3 locks held by events/0/9:

[   12.341044]  #0:  (events){--..}, at: [<ffffffff80253ef7>]
run_workqueue+0x107/0x230

[   12.341044]  #1:  ((dbs_work).work){--..}, at: [<ffffffff80253ef7>]
run_workqueue+0x107/0x230

[   12.341044]  #2:  (dbs_mutex){--..}, at: [<ffffffff805692f5>]
do_dbs_timer+0x25/0x250

[   12.341044]

[   12.341044] stack backtrace:

[   12.341044] Pid: 9, comm: events/0 Not tainted
2.6.29-rc1-00041-gacd1e11 #143
[   12.341044] Call Trace:

[   12.341044]  [<ffffffff80269e69>] validate_chain+0xb69/0x1200

[   12.341044]  [<ffffffff8026a93e>] __lock_acquire+0x43e/0xa50

[   12.341044]  [<ffffffff8026afa8>] lock_acquire+0x58/0x80

[   12.341044]  [<ffffffff80254783>] ? flush_work+0x33/0x100

[   12.341044]  [<ffffffff802547a8>] flush_work+0x58/0x100

[   12.341044]  [<ffffffff80254783>] ? flush_work+0x33/0x100

[   12.341044]  [<ffffffff80268b7d>] ? trace_hardirqs_on+0xd/0x10

[   12.341044]  [<ffffffff80254a3c>] ? __queue_work+0x3c/0x50

[   12.341044]  [<ffffffff80254ad4>] ? queue_work_on+0x44/0x60

[   12.341044]  [<ffffffff8021bd20>] ? do_drv_write+0x0/0x60

[   12.341044]  [<ffffffff8021bd20>] ? do_drv_write+0x0/0x60

[   12.341044]  [<ffffffff80254ba3>] work_on_cpu+0x93/0xc0

[   12.341044]  [<ffffffff80253cc0>] ? do_work_for_cpu+0x0/0x20

[   12.341044]  [<ffffffff8021bd20>] ? do_drv_write+0x0/0x60

[   12.341044]  [<ffffffff8025cba1>] ?
srcu_notifier_call_chain+0x11/0x20
[   12.341044]  [<ffffffff8021c5c9>] acpi_cpufreq_target+0x239/0x350

[   12.341044]  [<ffffffff80268af2>] ?
trace_hardirqs_on_caller+0x112/0x190
[   12.341044]  [<ffffffff80699ac8>] ? mutex_lock_nested+0x228/0x2f0

[   12.341044]  [<ffffffff80565731>] __cpufreq_driver_target+0x81/0x90

[   12.341044]  [<ffffffff8056940e>] do_dbs_timer+0x13e/0x250

[   12.341044]  [<ffffffff805692d0>] ? do_dbs_timer+0x0/0x250

[   12.341044]  [<ffffffff80253f49>] run_workqueue+0x159/0x230

[   12.341044]  [<ffffffff80253ef7>] ? run_workqueue+0x107/0x230

[   12.341044]  [<ffffffff80254d1f>] worker_thread+0xbf/0x120

[   12.341044]  [<ffffffff80258550>] ? autoremove_wake_function+0x0/0x40

[   12.341044]  [<ffffffff80254c60>] ? worker_thread+0x0/0x120

[   12.341044]  [<ffffffff8025811d>] kthread+0x4d/0x80

[   12.341044]  [<ffffffff8020c87a>] child_rip+0xa/0x20

[   12.341044]  [<ffffffff8020c27c>] ? restore_args+0x0/0x30
[   12.341044]  [<ffffffff802580d0>] ? kthread+0x0/0x80
[   12.341044]  [<ffffffff8020c870>] ? child_rip+0x0/0x20


complete log and config are attached.

The different git hash is because I reverted that revert patch. It is
exactly the same like the kernel on which I first found the problem,
only with some debugging enabled now. Maybe I should make more use of
gits capabilities...

Hope that helps,


> 
> 	Ingo
> 

cu
Dieter

-- 
3rd Law of Computing:
        Anything that can go wr
fortune: Segmentation violation -- Core dumped