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

Rik van Riel
2009-06-07T14:20:22Z

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@lwfinger.net>
>>> 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@sipsolutions.net>
>> 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.

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