Commit cf01537e authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul 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 */