| Date | Tue, 13 Oct 2020 16:15:08 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH 1/2] sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable() |
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On 2020-10-13 15:01:15 [+0100], Valentin Schneider wrote: > migrate_disable(); > set_cpus_allowed_ptr(current, {something excluding task_cpu(current)}); > affine_move_task(); <-- never returns > > Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> > --- > kernel/sched/core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 4ccd1099adaa..7f4e38819de1 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2189,6 +2189,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, > if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask)) > goto out; > > + if (p == current && > + is_migration_disabled(p) && > + !cpumask_test_cpu(task_cpu(p), new_mask)) > + ret = -EBUSY; > +
This shouldn't happen, right? The function may sleep so it shouldn't be entered with disabled migration. A WARN_ON might spot the bad caller.
Sebastian
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