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

From: Andrew Morton
Date: Wed Jul 23 2014 - 16:57:22 EST


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


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