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Date: Wed, 9 Jul 2014 15:59:39 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>,
        David Rientjes <rientjes@google.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
        Dave Jones <davej@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: fs: use after free in /proc/pid/mountinfo
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On Wed, 09 Jul 2014 18:10:47 -0400 Sasha Levin <sasha.levin@oracle.com> wrote:

> On 07/09/2014 04:31 PM, Andrew Morton wrote:
> > On Wed, 9 Jul 2014 16:24:06 +0200 Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
> > 
> >> > 058504edd026 ("fs/seq_file: fallback to vmalloc allocation") is suspected to
> >> > cause a crash. Actually I can't reprocude the crash nor would I be able to
> >> > tell how the commit could cause the crash.
> >> > Anyway, I'll be offline for the next 2.5 weeks. So if Sasha could confirm
> >> > that reverting the patch actually does fix the crash, please revert the
> >> > commit, unless somebody else can make sense of the report of course.
> >> > 
> >> > I'm still wondering how Sasha could reproduce the crash.
> > This really sucks :(
> > 
> > I suppose I'll queue up a revert of 058504edd026 as a for-3.16 bandaid.
> > 
> > Sasha, it would be great if you could delve a bit further into this,
> > see if we can identify a way for others to reproduce the bug.
> > 
> > Did you test that little patchlet which Heiko sent?
> 
> I've been trying, but as there isn't an easy way to reproduce it, breakage
> elsewhere in -next (there is a long list) is slowing me down. I'll revert
> back to the -next where I've initially observed this issue and will retry.
> 

Thanks.  The bug should be present in current mainline.