sched: add READ_ONCE to task_on_rq_queued

task_on_rq_queued read p->on_rq without READ_ONCE, though p->on_rq is
set with WRITE_ONCE in {activate|deactivate}_task and smp_store_release
in __block_task, and also read with READ_ONCE in task_on_rq_migrating.

Make all of these accesses pair together by adding READ_ONCE in the
task_on_rq_queued.

Signed-off-by: Harshit Agarwal <harshit@nutanix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20241114210812.1836587-1-jon@nutanix.com

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 76f5f53a645fcdc3de25c224813c7ac3b6aefa1a..0f6790c5279b3ebbee665f2df4e35d2ca99a1b72 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2271,7 +2271,7 @@ static inline int task_on_cpu(struct rq *rq, struct task_struct *p)
 
 static inline int task_on_rq_queued(struct task_struct *p)
 {
-       return p->on_rq == TASK_ON_RQ_QUEUED;
+       return READ_ONCE(p->on_rq) == TASK_ON_RQ_QUEUED;
 }
 
 static inline int task_on_rq_migrating(struct task_struct *p)