Re: v3.0: Weird kernel log message when resuming avout NMI received

[Francis Moreau]

Peter,

On Mon, Aug 15, 2011 at 10:37 AM, Francis Moreau <francis.moro@xxxxxxxxx> wrote:
> Hello Peter,
>
> Sorry for the loooonnng delay but summer rest :)
>
> On Mon, Aug 1, 2011 at 1:05 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
>> On Sun, 2011-07-31 at 19:32 +0400, Cyrill Gorcunov wrote:
>>
>>> > >> I'm seeing those kernel message when resuming:
>>> > >>
>>> > >> [  524.973283] Uhhuh. NMI received for unknown reason 3d on CPU 0.
>>> > >> [  524.973288] Do you have a strange power saving mode enabled?
>>> > >> [  524.973289] Dazed and confused, but trying to continue
>>> > >>
>>> > >> I don't know if it's important or not because the system seems to work
>>> > >> after but maybe it worths to report
>>
>> So I guess the problem is the NMI watchdog and suspend stuff not
>> shutting things down properly..
>>
>> Argh, the PM notifier muck runs before the hotplug notifiers and it
>> doesn't avoid hotplug races on its own.. what crap.
>>
>> something like the below perhaps, compile tested only.. does it work?
>
> Thanks for the fix, I'm going to give it a test and report in 2 days.
>

I'm trying to test the fix but have to stick with the 3.0 kernel and
your patch seems to be based on 3.1.

So I had to backport a couple of patches otherwise I'm getting the
following error:

  CC      kernel/events/core.o
kernel/events/core.c: In function ‘perf_pm_resume_cpu’:
kernel/events/core.c:7342: error: implicit declaration of function
‘perf_ctx_lock’
kernel/events/core.c:7350: error: implicit declaration of function
‘perf_ctx_unlock’
kernel/events/core.c: In function ‘perf_pm_suspend_cpu’:
kernel/events/core.c:7370: error: implicit declaration of function
‘perf_event_sched_in’

Here are the patches that I backported on top of 3.0:

 perf: Collect the schedule-in rules in one function
 perf: Change and simplify ctx::is_active semantics
 perf: Simplify and fix __perf_install_in_context()
 perf: Remove task_ctx_sched_in()
 perf: Optimize event scheduling locking
 perf: Clean up 'ctx' reference counting
 perf: Optimize ctx_sched_out()

After the second suspend/resume sequence I still have the same warning
except that the reason has changed to '2d':

 kernel:[  404.091393] Uhhuh. NMI received for unknown reason 2d on CPU 0.
 kernel:[  404.091394] Do you have a strange power saving mode enabled?
 kernel:[  404.091396] Dazed and confused, but trying to continue

Thanks
-- 
Francis
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