Re: fanotify use after free.
From: Jan Kara
Date: Thu Jan 23 2014 - 10:05:16 EST
On Wed 22-01-14 19:32:40, Dave Jones wrote:
> 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.
Drat. Since this seems reasonably reproducible, I'll try to reproduce
and debug this (it seems systemd is using fanotify in a way that triggers
this). Thanks for testing.
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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