Merge tag 'sched-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Various fixes: a deadline scheduler fix, a migration fix, a Sparse fix
  and a comment fix"

* tag 'sched-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Do not requeue task on CPU excluded from cpus_mask
  sched/rt: Fix Sparse warnings due to undefined rt.c declarations
  exit: Fix typo in comment: s/sub-theads/sub-threads
  sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed

1 files changed, 11 insertions, 5 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 189999007f32..ee28253c9ac0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3802,7 +3802,7 @@ bool cpus_share_cache(int this_cpu, int that_cpu)
 	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
 }
 
-static inline bool ttwu_queue_cond(int cpu)
+static inline bool ttwu_queue_cond(struct task_struct *p, int cpu)
 {
 	/*
 	 * Do not complicate things with the async wake_list while the CPU is
@@ -3811,6 +3811,10 @@ static inline bool ttwu_queue_cond(int cpu)
 	if (!cpu_active(cpu))
 		return false;
 
+	/* Ensure the task will still be allowed to run on the CPU. */
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
 	/*
 	 * If the CPU does not share cache, then queue the task on the
 	 * remote rqs wakelist to avoid accessing remote data.
@@ -3840,7 +3844,7 @@ static inline bool ttwu_queue_cond(int cpu)
 
 static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
 {
-	if (sched_feat(TTWU_QUEUE) && ttwu_queue_cond(cpu)) {
+	if (sched_feat(TTWU_QUEUE) && ttwu_queue_cond(p, cpu)) {
 		sched_clock_cpu(cpu); /* Sync clocks across CPUs */
 		__ttwu_queue_wakelist(p, cpu, wake_flags);
 		return true;
@@ -9012,7 +9016,7 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur,
 }
 
 int task_can_attach(struct task_struct *p,
-		    const struct cpumask *cs_cpus_allowed)
+		    const struct cpumask *cs_effective_cpus)
 {
 	int ret = 0;
 
@@ -9031,9 +9035,11 @@ int task_can_attach(struct task_struct *p,
 	}
 
 	if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
-					      cs_cpus_allowed)) {
-		int cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed);
+					      cs_effective_cpus)) {
+		int cpu = cpumask_any_and(cpu_active_mask, cs_effective_cpus);
 
+		if (unlikely(cpu >= nr_cpu_ids))
+			return -EINVAL;
 		ret = dl_cpu_busy(cpu, p);
 	}