Commit cf01537e authored Jun 21, 2012 by Paul E. McKenney Committed by Paul E. McKenney Jul 02, 2012

rcu: Add check for CPUs going offline with callbacks queued



If a CPU goes offline with callbacks queued, those callbacks might be
indefinitely postponed, which can result in a system hang.  This commit
therefore inserts warnings for this condition.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent 95f0c1de

kernel/rcutree.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1509,6 +1509,9 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp)
		raw_spin_unlock_irqrestore(&rnp->lock, flags);
		if (need_report & RCU_OFL_TASKS_EXP_GP)
		rcu_report_exp_rnp(rsp, rnp, true);
		WARN_ONCE(rdp->qlen != 0 \|\| rdp->nxtlist != NULL,
		"rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, nxtlist=%p\n",
		cpu, rdp->qlen, rdp->nxtlist);
		}

		#else /* #ifdef CONFIG_HOTPLUG_CPU */