From 59f792d1ef214592ae9b86238fa8fd00f5929b76 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 19 Jan 2015 21:43:40 -0800 Subject: [PATCH] rcu: Refine diagnostics for lacking kthread for no-CBs callbacks Some diagnostics under CONFIG_PROVE_RCU in rcu_nocb_cpu_needs_barrier() assume that there can be no early-boot callbacks. This commit therefore qualifies the diagnostic with rcu_scheduler_fully_active to permit early boot callbacks to avoid this splat. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 0a571e9a0f1d..75d5f096bcb0 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1945,7 +1945,8 @@ static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu) rhp = ACCESS_ONCE(rdp->nocb_follower_head); /* Having no rcuo kthread but CBs after scheduler starts is bad! */ - if (!ACCESS_ONCE(rdp->nocb_kthread) && rhp) { + if (!ACCESS_ONCE(rdp->nocb_kthread) && rhp && + rcu_scheduler_fully_active) { /* RCU callback enqueued before CPU first came online??? */ pr_err("RCU: Never-onlined no-CBs CPU %d has CB %p\n", cpu, rhp->func);