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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-06-21 18:26:42 (GMT)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-02 19:34:25 (GMT)
commitcf01537ecf192d9ff15c32a355db5d5af22bea4d (patch)
tree5561d7852d1a4dc88d706863f6c95256c783e9f4 /kernel
parent95f0c1de3e6ed4383cc4b5f52ce4ecfb21026b49 (diff)
downloadlinux-cf01537ecf192d9ff15c32a355db5d5af22bea4d.tar.xz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcutree.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e000a62..95c7b61 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -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 */