On Fri, Sep 04, 2026 at 09:01:05AM -0400, Mathieu Desnoyers wrote:
> On 2026-08-03 20:03, Bradley Morgan wrote:
> > The do_pending kthread never sleeps. Its supposed to.
> > kthread_do_pending_ms sets the gap between cleanups, and the docs
> > say so too. But the sleep sits behind torture_must_stop(), and thats
> > false while the test runs. So the kthread never sleeps. It just loops.
> > It drains the pending lists over and over, no pause, and burns a full
> > CPU for the whole test.
>
> Paul, I just found this patch in my junk email folder. Maybe relevant
> for you ?
We got it in my -rcu tree:
15b9fca2f5ce ("hazptrtorture: Fix inverted sleep condition in do_pending
kthread")
But I do appreciate your checking for missed patches, thank you!
Thanx, Paul
> Thanks,
>
> Mathieu
>
> >
> > Flip the check. With !torture_must_stop() it sleeps for
> > kthread_do_pending_ms between passes. When the test stops it does one
> > last cleanup and exits. Nothing left to do, so no sleep needed then.
> >
> > Fixes: 94d2e93c222e ("hazptrtorture: Add kthread to release deferred hazard
> > pointers")
> > Signed-off-by: Bradley Morgan <[email protected]>
> > ---
> > kernel/rcu/hazptrtorture.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/rcu/hazptrtorture.c b/kernel/rcu/hazptrtorture.c
> > index 72aeb50668e9..7c8b5899fb01 100644
> > --- a/kernel/rcu/hazptrtorture.c
> > +++ b/kernel/rcu/hazptrtorture.c
> > @@ -555,7 +555,7 @@ static int hazptr_torture_do_pending(void *arg)
> > cpu = cpumask_next_wrap(cpu, cpu_possible_mask);
> > hazptr_torture_do_one_pending(cpu, &rand);
> > }
> > - if (torture_must_stop())
> > + if (!torture_must_stop())
> > torture_hrtimeout_ms(kthread_do_pending_ms,
> > USEC_PER_MSEC, &rand);
> > // Omit stutter_wait() because this function needs to do
> > cleanup.
> > } while (!torture_must_stop());
>
>
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> https://www.efficios.com
