diff mbox series

[1/2] srcu: Check for concurrent updates of heuristics

Message ID 20240802003622.4134318-1-paulmck@kernel.org (mailing list archive)
State Accepted
Commit bd0d1697c5759b1543265bb59d6946acf9532bd0
Headers show
Series SRCU updates | expand

Commit Message

Paul E. McKenney Aug. 2, 2024, 12:36 a.m. UTC 
SRCU maintains the ->srcu_n_exp_nodelay and ->reschedule_count values
to guide heuristics governing auto-expediting of normal SRCU grace
periods and grace-period-state-machine delays.  This commit adds KCSAN
ASSERT_EXCLUSIVE_WRITER() calls to check for concurrent updates to
these fields.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/srcutree.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 48cd75b74f708..d3fdaeba0c10d 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -632,6 +632,7 @@  static unsigned long srcu_get_delay(struct srcu_struct *ssp)
 		if (time_after(j, gpstart))
 			jbase += j - gpstart;
 		if (!jbase) {
+			ASSERT_EXCLUSIVE_WRITER(sup->srcu_n_exp_nodelay);
 			WRITE_ONCE(sup->srcu_n_exp_nodelay, READ_ONCE(sup->srcu_n_exp_nodelay) + 1);
 			if (READ_ONCE(sup->srcu_n_exp_nodelay) > srcu_max_nodelay_phase)
 				jbase = 1;
@@ -1822,6 +1823,7 @@  static void process_srcu(struct work_struct *work)
 	} else {
 		j = jiffies;
 		if (READ_ONCE(sup->reschedule_jiffies) == j) {
+			ASSERT_EXCLUSIVE_WRITER(sup->reschedule_count);
 			WRITE_ONCE(sup->reschedule_count, READ_ONCE(sup->reschedule_count) + 1);
 			if (READ_ONCE(sup->reschedule_count) > srcu_max_nodelay)
 				curdelay = 1;