Re: INFO: possible circular locking dependency - kacpid acpi_os_wait_events_complete

From: Zdenek Kabelac
Date: Fri Sep 11 2009 - 03:48:54 EST


2009/8/26 Zdenek Kabelac <zdenek.kabelac@xxxxxxxxx>:
> 2009/8/25 Bjorn Helgaas <bjorn.helgaas@xxxxxx>:
>> On Tuesday 25 August 2009 02:33:30 pm you wrote:
>>> 2009/8/25 Bjorn Helgaas <bjorn.helgaas@xxxxxx>:
>>> > On Tuesday 25 August 2009 02:10:58 am Zdenek Kabelac wrote:
>>> >> Now with 2.6.31-rc7 (3edf2fb9d80a46d6c32ba12547a42419845b4b76)
>>> >>  I'm getting this  INFO trace - also I've noticed complete reset during resume
>>> >> which could be eventually related to this
>>> > Do you have any evidence that points to thinkpad_acpi?  I looked
>>> > at the recent changes there, and I don't see anything obviously
>>> > related to kacpid or deferred work.
>>> >
>>>
>>> Well I've never seen this INFO trace before - also I'm not sure I
>>> could reliable retest it - might be coincidence of suspend out of port
>>> replicator and resume while being attached on it - however I do this
>>> relatively often and I start to see this after I' started to use -rc7
>>> kernel.
>>>
>>> My guess is purely based on the fact that commit touching functions
>>> from INFO trace was recently merged to main tree.
>>>
>>> If there will be some time I could try to make few tests for suspend
>>> resume - but I hope the trace would be enough for analysis.
>>
>
> Well definitelly I do not have a reliable test case to
> deterministically trigger this INFO trace, but I think from the trace
> it looks like  the acpi_os_wait_events_complete calls flush_workqueue
> which again calls acpi_os_execute_hp_deferred which again tries to
> invoke flush_workqueue - so is that correct ?
>
> (__acpi_os_execute looks somewhat cryptic in selection what would be called)
>
> This is the stack traceback cut from my first post:
>
>  [<ffffffff81064df0>] ? flush_workqueue+0x0/0xc0
>  [<ffffffff81261532>] ? acpi_os_execute_hp_deferred+0x0/0x43
>  [<ffffffff81064e4f>] flush_workqueue+0x5f/0xc0
>  [<ffffffff81064df0>] ? flush_workqueue+0x0/0xc0
>  [<ffffffff81261524>] acpi_os_wait_events_complete+0x15/0x23
>  [<ffffffff81261561>] acpi_os_execute_hp_deferred+0x2f/0x43
>  [<ffffffff810651d4>] worker_thread+0x1e4/0x3f0
>
> So it looks like this issue is releated to commit:
> c02256be79a1a3557332ac51e653d574a2a7d2b5
>
> Hopefully the author would be able to fix this ?
>

Hi

Any progress with this issue - I'm still getting this INFO trace even
with 2.6.31

Zdenek
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