sched: Deny self-issued __set_cpus_allowed_ptr() when migrate_disable()
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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@arm.com
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e92d785..88c6fcb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2238,8 +2238,17 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
goto out;
}
- if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask))
- goto out;
+ if (!(flags & SCA_MIGRATE_ENABLE)) {
+ if (cpumask_equal(&p->cpus_mask, new_mask))
+ goto out;
+
+ if (WARN_ON_ONCE(p == current &&
+ is_migration_disabled(p) &&
+ !cpumask_test_cpu(task_cpu(p), new_mask))) {
+ ret = -EBUSY;
+ goto out;
+ }
+ }
/*
* Picking a ~random cpu helps in cases where we are changing affinity
