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-rw-r--r--kernel/sched/core.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 615953141951..f7402f7eb448 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2366,8 +2366,15 @@ void wake_up_new_task(struct task_struct *p)
trace_sched_wakeup_new(p);
check_preempt_curr(rq, p, WF_FORK);
#ifdef CONFIG_SMP
- if (p->sched_class->task_woken)
+ if (p->sched_class->task_woken) {
+ /*
+ * Nothing relies on rq->lock after this, so its fine to
+ * drop it.
+ */
+ lockdep_unpin_lock(&rq->lock);
p->sched_class->task_woken(rq, p);
+ lockdep_pin_lock(&rq->lock);
+ }
#endif
task_rq_unlock(rq, p, &flags);
}
@@ -2517,11 +2524,11 @@ static struct rq *finish_task_switch(struct task_struct *prev)
* If a task dies, then it sets TASK_DEAD in tsk->state and calls
* schedule one last time. The schedule call will never return, and
* the scheduled task must drop that reference.
- * The test for TASK_DEAD must occur while the runqueue locks are
- * still held, otherwise prev could be scheduled on another cpu, die
- * there before we look at prev->state, and then the reference would
- * be dropped twice.
- * Manfred Spraul <manfred@colorfullife.com>
+ *
+ * We must observe prev->state before clearing prev->on_cpu (in
+ * finish_lock_switch), otherwise a concurrent wakeup can get prev
+ * running on another CPU and we could rave with its RUNNING -> DEAD
+ * transition, resulting in a double drop.
*/
prev_state = prev->state;
vtime_task_switch(prev);
@@ -4022,6 +4029,7 @@ int sched_setscheduler_nocheck(struct task_struct *p, int policy,
{
return _sched_setscheduler(p, policy, param, false);
}
+EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
static int
do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
@@ -7238,9 +7246,6 @@ void __init sched_init_smp(void)
alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
- /* nohz_full won't take effect without isolating the cpus. */
- tick_nohz_full_add_cpus_to(cpu_isolated_map);
-
sched_init_numa();
/*
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