Commit 6d60ea03 authored by Zqiang's avatar Zqiang Committed by Paul E. McKenney
Browse files

rcu: Fix rcu_read_unlock_strict() strict QS reporting 



Kernels built with CONFIG_PREEMPT=n and CONFIG_RCU_STRICT_GRACE_PERIOD=y
report the quiescent state directly from the outermost rcu_read_unlock().
However, the current CPU's rcu_data structure's ->cpu_no_qs.b.norm
might still be set, in which case rcu_report_qs_rdp() will exit early,
thus failing to report quiescent state.

This commit therefore causes rcu_read_unlock_strict() to clear
CPU's rcu_data structure's ->cpu_no_qs.b.norm field before invoking
rcu_report_qs_rdp().

Signed-off-by: default avatarZqiang <qiang1.zhang@intel.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 568035b0

kernel/rcu/tree_plugin.h

+1 −0
Original line number Diff line number Diff line
@@ -824,6 +824,7 @@ void rcu_read_unlock_strict(void) 
	if (irqs_disabled() || preempt_count() || !rcu_state.gp_kthread)

		return;

	rdp = this_cpu_ptr(&rcu_data);

	rdp->cpu_no_qs.b.norm = false;

	rcu_report_qs_rdp(rdp);

	udelay(rcu_unlock_delay);

}