[PATCH rcu 1/3] rcu/kfree: Warn on unexpected tail state

neeraj.upadhyay
2024-08-16T07:23:33Z

From: "Paul E. McKenney" <paulmck@kernel.org>

Within the rcu_sr_normal_gp_cleanup_work() function, there is an acquire
load from rcu_state.srs_done_tail, which is expected to be non-NULL.
This commit adds a WARN_ON_ONCE() to check this expectation.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e641cc681901..0f41a81138dc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1649,7 +1649,7 @@ static void rcu_sr_normal_gp_cleanup_work(struct work_struct *work)
* the done tail list manipulations are protected here.
*/
done = smp_load_acquire(&rcu_state.srs_done_tail);
- if (!done)
+ if (WARN_ON_ONCE(!done))
return;

WARN_ON_ONCE(!rcu_sr_is_wait_head(done));
--
2.40.1