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From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Jonathan Woithe <jwoithe@atrad.com.au>
Cc: David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: OOM triggered with plenty of memory free
Date: Tue, 26 Feb 2013 07:26:45 -0800	[thread overview]
Message-ID: <512CD435.30704@linux.vnet.ibm.com> (raw)
In-Reply-To: <20130226063916.GM16712@marvin.atrad.com.au>

On 02/25/2013 10:39 PM, Jonathan Woithe wrote:
> On Wed, Feb 13, 2013 at 07:14:50AM -0800, Dave Hansen wrote:
>> David's analysis looks spot-on.  The only other thing I'll add is that
>> it just looks weird that all three kmalloc() caches are so _even_:
>>
>>>> kmalloc-128       1234556 1235168    128   32    1 : tunables    0    0    0 : slabdata  38599  38599      0
>>>> kmalloc-64        1238117 1238144     64   64    1 : tunables    0    0    0 : slabdata  19346  19346      0
>>>> kmalloc-32        1236600 1236608     32  128    1 : tunables    0    0    0 : slabdata   9661   9661      0
>>
>> It's almost like something goes and does 3 allocations in series and
>> leaks them all.
...
> Given these observations it seems that 2.6.35.11 was leaking memory,
> probably as a result of a bug in the fork() execution path.  At this stage
> kmemleak is not showing the same recurring problem under 3.7.9.

Your kmemleak data shows that the leaks are always from either 'struct
cred', or 'struct pid'.  Those are _generally_ tied to tasks, but you
only have a couple thousand task_structs.

My suspicion would be that something is allocating those structures, but
a refcount got leaked somewhere.  2.6.35.11 is about the same era that
this code went in:

http://lists.linux-foundation.org/pipermail/containers/2010-June/024720.html

and it deals with both creds and 'struct pid'.  Eric, do you recall any
bugs like this that got fixed along the way?

I do think it's fairly safe to assume that 3.7.9 doesn't have this bug.

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  reply	other threads:[~2013-02-26 15:34 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-13  3:10 OOM triggered with plenty of memory free Jonathan Woithe
2013-02-13  3:30 ` David Rientjes
2013-02-13  4:25   ` Jonathan Woithe
2013-02-13 15:14     ` Dave Hansen
2013-02-13 22:49       ` Jonathan Woithe
2013-02-21  6:01       ` Jonathan Woithe
2013-02-26  6:39       ` Jonathan Woithe
2013-02-26 15:26         ` Dave Hansen [this message]
2013-02-26 20:54           ` Eric W. Biederman
2013-03-04  5:25             ` Jonathan Woithe
2013-02-20  5:50   ` Simon Jeons
2013-02-20  7:05     ` David Rientjes
  -- strict thread matches above, loose matches on Subject: below --
2013-03-16  9:25 Hillf Danton
2013-03-16  9:33 ` Raymond Jennings
2013-03-16 11:02   ` Jonathan Woithe
2013-03-20  5:47   ` Jonathan Woithe
2013-03-21  7:07   ` Jonathan Woithe
2013-03-25  2:24     ` Jonathan Woithe

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