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

Thomas Gleixner
2014-06-21T19:55:10Z

On Wed, 18 Jun 2014, Steven Rostedt wrote:

> On Wed, 18 Jun 2014 18:43:59 +0200
> Oleg Nesterov <oleg@redhat.com> wrote:
>
>
> > And (contrary to what I said initially) we can rely on this because -rt
> > converts spinlock_t into rt_mutex ?
>
> Correct. Because if spinlock_t has this behavior, rt_mutex must have it
> too, otherwise -rt will suffer greatly from that. Who knows, maybe this
> will fix some strange bug reports that we have had in the past.

Indeed. I found a few backtraces from Carstens test farm, where stuff
explodes in the slowpath raw_spin_unlock call. Happens once a year or
never ...

Thanks,

tglx