rcu: Refine diagnostics for lacking kthread for no-CBs callbacks (59f792d1) · Commits · 戴 / test

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 <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree_plugin.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

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