Sebastian,
On Wed, 22 Aug 2018 12:17:49 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Sun, 19 Aug 2018 08:28:35 +0200
> Mike Galbraith <efault@xxxxxx> wrote:
>
> > On Sat, 2018-08-18 at 15:13 +0200, Mike Galbraith wrote:
> > > seems it has be something from the 4.17 cycle that went back to 4.14-
> > > stable after 4.1[56]-stable trees went extinct.
> >
> > See ("sched/core: Require cpu_active() in select_task_rq(), for user tasks")
> >
> > Fix it like so?
> >
> > sched: Allow pinned user tasks to be awakened to the CPU they pinned
> >
> > Since 7af443ee16976, select_fallback_rq() will BUG() if the CPU to
> > which a task has pinned itself and pinned becomes !cpu_active()
> > while it slept. Serving a 10 megaton eviction notice is neither
> > helpful nor required, the task will migrate when it can do so.
>
> This seems to fix the issue that I was seeing. Thanks!
>
> I'll add this to my repo as well.
I'm going to hold off on pulling this in until I see it in your tree,
because a stable RT branch should not carry anything that isn't in the
head RT tree. And it appears that this can affect your repo too.
-- Steve
>
> >
> > Signed-off-by: Mike Galbraith <efault@xxxxxx>
> > ---
> > kernel/sched/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -980,7 +980,7 @@ static inline bool is_cpu_allowed(struct
> > if (!cpumask_test_cpu(cpu, p->cpus_ptr))
> > return false;
> >
> > - if (is_per_cpu_kthread(p))
> > + if (is_per_cpu_kthread(p) || __migrate_disabled(p))
> > return cpu_online(cpu);
> >
> > return cpu_active(cpu);
>
