Commit 2406fb8d authored Aug 13, 2018 by Linus Torvalds

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 bugfix to prevent a pinned thread which queues stomp machine
  work to be preempted by the stopper thread on its CPU which causes a
  live lock as it is unable to wake the second CPUs stopper thread"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  stop_machine: Atomically queue and wake stopper threads

parents 37a16046 cfd35514

kernel/stop_machine.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -81,6 +81,7 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
		unsigned long flags;
		bool enabled;

		preempt_disable();
		raw_spin_lock_irqsave(&stopper->lock, flags);
		enabled = stopper->enabled;
		if (enabled)
		@@ -90,6 +91,7 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
		raw_spin_unlock_irqrestore(&stopper->lock, flags);

		wake_up_q(&wakeq);
		preempt_enable();

		return enabled;
		}

Admin message