[PATCH] rcu: Add missing __releases() annotation

[PATCH] rcu: Add missing __releases() annotation

[Jules Irenge]

Sparse report a warning at rcu_print_task_stall()

"warning: context imbalance in rcu_print_task_stall - unexpected unlock"

The root cause is a missing annotation at  rcu_print_task_stall() function

Add the missing __releases(rnp->lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
---
 kernel/rcu/tree_stall.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 59b95cc5cbdf..18b2d5274d65 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -314,6 +314,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
  * tasks blocked within RCU read-side critical sections.
  */
 static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
 {
 	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 	return 0;
-- 
2.31.1

Re: [PATCH] rcu: Add missing __releases() annotation

[Paul E. McKenney]

On Thu, Apr 29, 2021 at 12:12:19AM +0100, Jules Irenge wrote:
> Sparse report a warning at rcu_print_task_stall()
> 
> "warning: context imbalance in rcu_print_task_stall - unexpected unlock"
> 
> The root cause is a missing annotation at  rcu_print_task_stall() function
> 
> Add the missing __releases(rnp->lock) annotation
> 
> Signed-off-by: Jules Irenge <jbi.octave@gmail.com>

Good catch, applied, thank you!

							Thanx, Paul

> ---
>  kernel/rcu/tree_stall.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
> index 59b95cc5cbdf..18b2d5274d65 100644
> --- a/kernel/rcu/tree_stall.h
> +++ b/kernel/rcu/tree_stall.h
> @@ -314,6 +314,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
>   * tasks blocked within RCU read-side critical sections.
>   */
>  static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
> +	__releases(rnp->lock)
>  {
>  	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
>  	return 0;
> -- 
> 2.31.1
>