[Patch v4 07/16] sched/cache: Fix rcu warning when accessing sd_llc domain

[Tim Chen]

From: Chen Yu <yu.c.chen@xxxxxxxxx>

rcu_dereference_all() should be used to access the
sd_llc domain under RCU protection.

This bug was reported by sashiko.

Fixes: df0d98475954 ("sched/cache: Introduce infrastructure for cache-aware load balancing")
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
Co-developed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 01ce646792ff..be96d80c9310 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1814,7 +1814,7 @@ static void task_cache_work(struct callback_head *work)
 
 		for_each_cpu(cpu, cpus) {
 			/* XXX sched_cluster_active */
-			struct sched_domain *sd = per_cpu(sd_llc, cpu);
+			struct sched_domain *sd = rcu_dereference_all(per_cpu(sd_llc, cpu));
 			unsigned long occ, m_occ = 0, a_occ = 0;
 			int m_cpu = -1, i;
 
-- 
2.32.0