Re: fs: use after free in /proc/pid/mountinfo

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 15 Jul 2014 16:01:34 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:

> On Tue, 15 Jul 2014, Sasha Levin wrote:
> 
> > I've been running mainline for a while, and while I can reproduce a different
> > bug for Hugh, I can't reproduce this one at all. Not sure how to call it now,
> > maybe memory corruption from somewhere else (I did find an unrelated memory
> > corruption couple days ago)?
> > 
> 
> I have a very large /proc/pid/mountinfo on one of my busy systems with VM 
> and slub debugging enabled and have not been able to reproduce the issue 
> while reading it in a loop for 24 hours.  I would call the patch good on 
> that basis, but it's very strange you'd report this problem a day after 
> the patch was merged and could not reproduce it once it was reverted.  
> (Unless the patch was misapplied locally and reapplying it now worked, but 
> I doubt you originally merged -mm patches into a local tree yourself.)

I was going to revert "fs/seq_file: fallback to vmalloc allocation" but
the idea of doing that is so lame and pathetic that I think I'll not do
that.  If we have a bug then let's just find and fix it when someone is
able to trigger it.