Re: [patch] futex: Cure exit race

[Thomas Gleixner]

On 2018-12-18 10:31, Thomas Gleixner wrote:
> On Wed, 12 Dec 2018, Peter Zijlstra wrote:
> > On Mon, Dec 10, 2018 at 06:43:51PM +0100, Thomas Gleixner wrote:
> > @@ -806,6 +806,8 @@ void __noreturn do_exit(long code)
> >  		 * task into the wait for ever nirwana as well.
> >  		 */
> >  		tsk->flags |= PF_EXITPIDONE;
> > +		smp_mb();
> > +		wake_up_bit(&tsk->flags, 3 /* PF_EXITPIDONE */);
>
> Using ilog2(PF_EXITPIDONE) spares that horrible inline comment and 
> more
> importantly selects the right bit. 0x04 is bit 2 ....

Plus wake_up_bit() and wait_on_bit() want an unsigned long, but 
tsk->flags is
unsigned int....

Moar staring....