From: Lai Jiangshan on
Warning: I just did build test.

Subject: [PATCH] rcu: more careful check for the last non-dyntick-idle CPU

If a CPU is not in nohz_cpu_mask, it does not means this
CPU is a non-dyntick-idle CPU, because this CPU may be offline or not exist.

Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com>
---
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 4befb64..6086a7d 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1026,7 +1026,7 @@ int rcu_needs_cpu(int cpu)

/* Don't bother unless we are the last non-dyntick-idle CPU. */
for_each_cpu_not(thatcpu, nohz_cpu_mask)
- if (thatcpu != cpu) {
+ if (cpu_online(thatcpu) && thatcpu != cpu) {
per_cpu(rcu_dyntick_drain, cpu) = 0;
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
return rcu_needs_cpu_quick_check(cpu);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/