How to debug system freeze?

How to debug system freeze?

[Łukasz Sowa]

Hi,

I'm experiencing strange bug when I close lid of my laptop - system
freezes (no reaction on keys, no response form ssh) hard and displays
some strange colour effects. The kernel log (after reboot) shows
nothing. My question is - how to debug it? Maybe there's a way to track
last called kernel function or something similar?

Thanks,
Lukasz Sowa

How to debug system freeze?

[Mulyadi Santosa]

Hi...

On Fri, Feb 24, 2012 at 02:52, ?ukasz Sowa <luksow@gmail.com> wrote:
> Hi,
>
> I'm experiencing strange bug when I close lid of my laptop - system
> freezes (no reaction on keys, no response form ssh) hard and displays
> some strange colour effects. The kernel log (after reboot) shows
> nothing. My question is - how to debug it? Maybe there's a way to track
> last called kernel function or something similar?

Hm, sounds like a bug during suspend. Perhaps you can do "strace
pm-suspend". And/or enable CONFIG_DETECT_SOFTLOCKUP. And hopefully you
can pinpoint the related syscall or kernel instruction that leads to
the bug

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

How to debug system freeze?

[Łukasz Sowa]

> 
> Hm, sounds like a bug during suspend. Perhaps you can do "strace
> pm-suspend". And/or enable CONFIG_DETECT_SOFTLOCKUP. And hopefully you
> can pinpoint the related syscall or kernel instruction that leads to
> the bug
> 

It's not that easy. The problem occurs only when I'm going to suspend
with closing laptop's lid and it does not happen every time (but mostly
yes). I'll try to enable CONFIG_DETECT_SOFTLOCKUP but if it's hard
freeze, will I see the output?

Regards,
Lukasz Sowa

How to debug system freeze?

[Mulyadi Santosa]

Hi Lukasz :)

On Sat, Feb 25, 2012 at 07:17, ?ukasz Sowa <luksow@gmail.com> wrote:
> It's not that easy. The problem occurs only when I'm going to suspend
> with closing laptop's lid and it does not happen every time (but mostly
> yes). I'll try to enable CONFIG_DETECT_SOFTLOCKUP but if it's hard
> freeze, will I see the output?

not everytime...ok that makes situation harder. Maybe you need serial
console and hook another computer to see the kernel log.

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

How to debug system freeze?

[Łukasz Sowa]

Thanks Mulyadi,

> Hi Lukasz :)
> 
> On Sat, Feb 25, 2012 at 07:17, ?ukasz Sowa <luksow@gmail.com> wrote:
>> It's not that easy. The problem occurs only when I'm going to suspend
>> with closing laptop's lid and it does not happen every time (but mostly
>> yes). I'll try to enable CONFIG_DETECT_SOFTLOCKUP but if it's hard
>> freeze, will I see the output?
> 
> not everytime...ok that makes situation harder. Maybe you need serial
> console and hook another computer to see the kernel log.
> 

I'll try to dump memory using FireWire because that's only useful port I
have in my laptop. Is that ok?

Regards,
Lukasz Sowa

How to debug system freeze?

[Mulyadi Santosa]

Hi Lukasz :)

On Mon, Feb 27, 2012 at 08:31, ?ukasz Sowa <luksow@gmail.com> wrote:
> I'll try to dump memory using FireWire because that's only useful port I
> have in my laptop. Is that ok?

I can't tell for sure, but that sounds feasible. Good luck....


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

How to debug system freeze?

[Srivatsa Bhat]

On Fri, Feb 24, 2012 at 1:22 AM, ?ukasz Sowa <luksow@gmail.com> wrote:

> Hi,
>
> I'm experiencing strange bug when I close lid of my laptop - system
> freezes (no reaction on keys, no response form ssh) hard and displays
> some strange colour effects. The kernel log (after reboot) shows
> nothing. My question is - how to debug it? Maybe there's a way to track
> last called kernel function or something similar?
>
>
Maybe you can try the pm_test framework (see Documentation/power/basic-pm-
debugging.txt) to narrow down the problem.

Regards,
Srivatsa S. Bhat
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