Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Thomas Gleixner:
 "A single bug fix for the scheduler to prevent dequeueing of the idle
  task when setting the cpus allowed mask"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix crash trying to dequeue/enqueue the idle thread
This commit is contained in:
Linus Torvalds 2015-09-27 12:50:27 -04:00
commit 73f479b243
1 changed files with 11 additions and 3 deletions

View File

@ -4934,7 +4934,15 @@ void init_idle(struct task_struct *idle, int cpu)
idle->state = TASK_RUNNING;
idle->se.exec_start = sched_clock();
do_set_cpus_allowed(idle, cpumask_of(cpu));
#ifdef CONFIG_SMP
/*
* Its possible that init_idle() gets called multiple times on a task,
* in that case do_set_cpus_allowed() will not do the right thing.
*
* And since this is boot we can forgo the serialization.
*/
set_cpus_allowed_common(idle, cpumask_of(cpu));
#endif
/*
* We're having a chicken and egg problem, even though we are
* holding rq->lock, the cpu isn't yet set to this cpu so the
@ -4951,7 +4959,7 @@ void init_idle(struct task_struct *idle, int cpu)
rq->curr = rq->idle = idle;
idle->on_rq = TASK_ON_RQ_QUEUED;
#if defined(CONFIG_SMP)
#ifdef CONFIG_SMP
idle->on_cpu = 1;
#endif
raw_spin_unlock(&rq->lock);
@ -4966,7 +4974,7 @@ void init_idle(struct task_struct *idle, int cpu)
idle->sched_class = &idle_sched_class;
ftrace_graph_init_idle_task(idle, cpu);
vtime_init_idle(idle, cpu);
#if defined(CONFIG_SMP)
#ifdef CONFIG_SMP
sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
#endif
}