Alleged fix for CPU-hotplug deadlock

RFC PATCH New Paul E. McKenney 1 participant 1 message Feb 21, 2012

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Paul E. McKenney

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2012-02-21 20:00 UTC #0 lore raw

RFC PATCH 1/1 Alleged fix for CPU-hotplug deadlock

This patch is intended to fix a deadlock seen in -rt. Untested, might not even compile. The intent is to move kthread_stop() outside of the CPU-hotplug lock, thus preventing deadlocks involving sleeping spinlocks.

Signed-off-by Paul E. McKenney <[email protected]>

kernel/rcutree.c +1 -2

index 8c26a49..e0d514b 100644
@@ -2041,8 +2041,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
 		rcu_send_cbs_to_online(&rcu_sched_state);
 		rcu_preempt_send_cbs_to_online();
 		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
+	case CPU_POST_DEAD:
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 		rcu_offline_cpu(cpu);