Re: OOM killer, page fault

[Minchan Kim <minchan.kim@gmail.com>]

Hi.

On Thu, Nov 5, 2009 at 10:21 PM, Norbert Preining <preining@logic.at> wrote:
> Hi Kim, hi all,
>
> (still please Cc)
>
> sorry for the late reply. I have two news, one good and one bad: The good
> being that I can reproduce the bug by running VirtualBox with some W7

W7 means "Windows 7"?

> within. Anyway, I don't have a trace or better debug due to the bad news:
> Both 2.6.32-rc5 and 2.6.32-rc6 do *not* boot with the patch below.
> Don't ask me why, please, and I don't have a serial/net console so that
> I can tell you more, but the booting hangs badly at:
> [    6.657492] usb 4-1: Product: Globetrotter HSDPA Modem
> [    6.657494] usb 4-1: Manufacturer: Option N.V.
> [    6.657496] usb 4-1: SerialNumber: Serial Number
> [    6.657558] usb 4-1: configuration #1 chosen from 1 choice
> [    6.837364] input: PS/2 Mouse as /devices/platform/i8042/serio2/input/input6
> [    6.853693] input: AlpsPS/2 ALPS GlidePoint as /devices/platform/i8042/serio2/input/input7
>
> Normally it continues like that, but with the patch below it hangs here
> and does not continue. I need to Sysrq-s/u/b out of it.
>
> [    6.904119] usb 8-2: new full speed USB device using uhci_hcd and address 2
> [    7.075524] usb 8-2: New USB device found, idVendor=044e, idProduct=3017
>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 7e91b5f..47e4b15 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -2713,7 +2713,11 @@ static int __do_fault(struct mm_struct *mm,
>> struct vm_area_struct *vma,
>>        vmf.page = NULL;
>>
>>        ret = vma->vm_ops->fault(vma, &vmf);
>> -       if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
>> +       if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
>> +               printk(KERN_DEBUG "vma->vm_ops->fault : 0x%lx\n",
>> vma->vm_ops->fault);
>> +               WARN_ON(1);
>> +
>> +       }
>>                return ret;
>>
>>        if (unlikely(PageHWPoison(vmf.page))) {
>
> I know it sounds completely crazy, the patch only does harmless things
> afais. But I tried it. Several times. rc6+patch never did boot, while
> rc5 without path did boot. Then I patched it into -rc5, recompiled, and
> boom, no boot. booting into .31.5, recompiling rc6 and rc5 without
> that patch and suddenly rc6 boots (and I am sure rc5, too).

Hmm. It's out of my knowledge.
Probably, It's because WARN_ON?
Could you try it with omitting WARN_ON, again?

>
> Sorry that I cannot give more infos, please let me know what else I can
> do.

Thanks for your time :)

> Ah yes, I can reproduce the original strange bug with oom killer!

Sounds good to me.
Could you tell me your test scenario, your system info(CPU, RAM) and
config?
I want to reproduce it in my mahchine to not bother you. :)


>
> Best wishes
>
> Norbert
>
> -------------------------------------------------------------------------------
> Dr. Norbert Preining                                        Associate Professor
> JAIST Japan Advanced Institute of Science and Technology   preining@jaist.ac.jp
> Vienna University of Technology                               preining@logic.at
> Debian Developer (Debian TeX Task Force)                    preining@debian.org
> gpg DSA: 0x09C5B094      fp: 14DF 2E6C 0307 BE6D AD76  A9C0 D2BF 4AA3 09C5 B094
> -------------------------------------------------------------------------------
> MELTON CONSTABLE (n.)
> A patent anti-wrinkle cream which policemen wear to keep themselves
> looking young.
>                        --- Douglas Adams, The Meaning of Liff
>



-- 
Kind regards,
Minchan Kim

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