Re: fanotify use after free.

From: Dave Jones
Date: Wed Jan 22 2014 - 19:32:59 EST


On Wed, Jan 22, 2014 at 04:08:52PM -0800, Linus Torvalds wrote:
> On Wed, Jan 22, 2014 at 3:36 PM, Jan Kara <jack@xxxxxxx> wrote:
> >
> > But refcounting seems like an overkill for this - there is exactly one
> > fanotify_response_event structure iff it is a permission event. So
> > something like the (completely untested) attached patch should fix the
> > problem. But I agree it's a bit ugly so we might want something different.
> > I'll try to think about something better tomorrow.
>
> Ok, In the meantime, Dave, can you verify whether this hacky patch
> fixes your problem?

It actually seems worse. I see the tail end of what looks like a slab corruption
trace, and then a total lockup. And of course none of this makes it over ttyUSB0
because it happens so early. Grr.

Dave

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