On 25/07/24(Thu) 14:51, Claudio Jeker wrote:
> On Thu, Jul 25, 2024 at 11:09:44AM +0200, Martin Pieuchot wrote:
> [...]
> > > Index: kern/kern_synch.c
> > > ===================================================================
> > > RCS file: /cvs/src/sys/kern/kern_synch.c,v
> > > diff -u -p -r1.206 kern_synch.c
> > > --- kern/kern_synch.c 23 Jul 2024 08:38:02 -0000 1.206
> > > +++ kern/kern_synch.c 24 Jul 2024 14:14:06 -0000
> > > @@ -399,15 +399,18 @@ sleep_finish(int timo, int do_sleep)
> > > */
> > > if (p->p_wchan == NULL)
> > > do_sleep = 0;
> > > + KASSERT((p->p_flag & P_SINGLESLEEP) == 0);
> > > atomic_clearbits_int(&p->p_flag, P_WSLEEP);
> > >
> > > + /* If requested to stop always force a stop even if do_sleep == 0 */
> > > + if (p->p_stat == SSTOP)
> > > + do_sleep = 1;
> >
> > This is also scary. The problem with the current scheme is that we don't
> > know who changed `p_stat' and if we already did our context switch or
> > not.
>
> It is scary indeed. I would prefer if sleep_signal_check() would not
> randomly mi_switch() away behind our back. I first tried that but it is
> harder then you think.
So maybe let's start by adding:
KASSERT(!(p->p_stat == SSTOP && do_sleep == 0))
And see if something blows.
