diff mbox series

[01/10] rcu: Fix rcu_read_unlock_strict() strict QS reporting

Message ID 20220831180805.2693546-1-paulmck@kernel.org (mailing list archive)
State New, archived
Headers show
Series Miscellaneous fixes for v6.1 | expand

Commit Message

Paul E. McKenney Aug. 31, 2022, 6:07 p.m. UTC 
From: Zqiang <qiang1.zhang@intel.com>

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: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree_plugin.h | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 438ecae6bd7e7..86772c95ed0ae 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -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);
 }