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Date: Wed, 23 Apr 2008 10:13:11 -0700
From: Pete Zaitcev <zaitcev@redhat.com>
To: "Pekka Enberg" <penberg@cs.helsinki.fi>
Cc: "Ingo Molnar" <mingo@elte.hu>, "Frans Pop" <elendil@planet.nl>,
       linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, gregkh@suse.de,
       "Christoph Lameter" <clameter@sgi.com>
Subject: Re: [sched-devel/latest] WARNING: at mm/slub.c:2443
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On Wed, 23 Apr 2008 10:34:57 +0300, "Pekka Enberg" <penberg@cs.helsinki.fi> wrote:
> On Wed, Apr 23, 2008 at 10:31 AM, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> >  On Wed, Apr 23, 2008 at 9:51 AM, Pete Zaitcev <zaitcev@redhat.com> wrote:

> >  >  I looked at this whole day today, but found nothing.
> >  >
> >  >  The code analysis for usbmon shows nothing. Anyone wants to have
> >  >  a look?
> 
> >  I didn't look too closely but mon_text_fetch() does list_del() but no
> >  kmem_cache_free() which looks fishy.
> 
> Yup, looks like a leak in the error path. So it's mon_text_read_t() ->
> mon_text_read_wait() -> mon_text_fetch() that removes it from the list
> but we can fail before we reach the kmem_cache_free() in
> mon_text_read_t() and thus lose track of the object.

This is false, we cannot fail. There's only one "return" for non-NULL
case and the kmem_cache_free is right in front of it. See my reply
to the patch.

-- Pete