Re: [Bug #13319] Page allocation failures with b43 and p54usb

Pekka Enberg
2009-06-07T14:32:52Z

On Sun, Jun 7, 2009 at 5:19 PM, Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> Pekka Enberg wrote:
>>
>> Hi Larry,
>>
>> On Sun, Jun 7, 2009 at 4:10 PM, Larry Finger <Larry.Finger@lwfinger.net>
>> wrote:
>>>
>>> Rafael J. Wysocki wrote:
>>>>
>>>> This message has been generated automatically as a part of a report
>>>> of recent regressions.
>>>>
>>>> The following bug entry is on the current list of known regressions
>>>> from 2.6.29.  Please verify if it still should be listed and let me know
>>>> (either way).
>>>>
>>>>
>>>> Bug-Entry     : http://bugzilla.kernel.org/show_bug.cgi?id=13319
>>>> Subject               : Page allocation failures with b43 and p54usb
>>>> Submitter     : Larry Finger <Larry.Finger-tQ5ms3gMjBLk1uMJSBkQmQ@public.gmane.org>
>>>> Date          : 2009-04-29 21:01 (40 days old)
>>>> References    : http://marc.info/?l=linux-kernel&m=124103897101088&w=4
>>>> Handled-By    : Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
>>>
>>> This bug is extremely difficult to pin down. I cannot reproduce it at
>>> will. The system has to be up for a long time, which is difficult with
>>> testing the late RC's of 2.6.30 and the code in wireless-testing so
>>> that new bugs don't end up in 2.6.31-RCX. That said, it still was in
>>> 2.6.30-RC6 and I'm not aware of any changes since that would fix it.
>>>
>>> My operating kernel is patched with additional diagnostics to help me
>>> understand why a kmalloc request for a buffer of 1390 bytes suddenly
>>> ends up as an O(1) request. Unfortunately, I don't have any answers.
>>
>> Looking at the out-of-memory trace, there's still memory available but
>> the pskb_expand_head() allocation is GFP_ATOMIC so there's not much
>> the page allocator can do here. The amount of memory consumed by
>> inactive_file is pretty high so maybe the problem is related to the
>> recent mm/vmscan.c changes. Lets copy some more mm developers and see
>> if they can help out.
>
> That is a very strange trace.  The Mem-Info indicates
> that the system has more than enough memory free, and
> also enough memory in higher-order free blocks.
>
> This would indicate a bug somewhere in the page
> allocator - this memory should have been given to this
> allocation request.

Aha, I always have difficulties deciphering the traces. But lets
invite Mel to the party then!

Pekka