Re: safety of *mutex_unlock() (Was: [BUG] signal: sighand unprotected when accessed by /proc)

Steven Rostedt
2014-06-09T18:30:03Z

On Mon, 9 Jun 2014 20:15:53 +0200
Oleg Nesterov <oleg@redhat.com> wrote:

> > That would indeed be a bad thing, as it could potentially lead to
> > use-after-free bugs. Though one could argue that any code that resulted
> > in use-after-free would be quite aggressive. But still...
>
> And once again, note that the normal mutex is already unsafe (unless I missed
> something).

Is it unsafe?

This thread was started because of a bug we triggered in -rt, which
ended up being a change specific to -rt that modified the way slub
handled SLAB_DESTROY_BY_RCU. What else was wrong with it?

-- Steve