From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 26 Sep 2024 14:51:07 +0200

A put_task_struct() call was immediately used after a return value check
for a scx_ops_init_task() call in this function implementation.
Thus call such a function only once instead directly before the check.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/sched/ext.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 9ee5a9a261cc..4b89ea20e355 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -5091,8 +5091,8 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link)
 		spin_unlock_irq(&scx_tasks_lock);

 		ret = scx_ops_init_task(p, task_group(p), false);
+		put_task_struct(p);
 		if (ret) {
-			put_task_struct(p);
 			spin_lock_irq(&scx_tasks_lock);
 			scx_task_iter_exit(&sti);
 			spin_unlock_irq(&scx_tasks_lock);
@@ -5101,7 +5101,6 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link)
 			goto err_disable_unlock_all;
 		}

-		put_task_struct(p);
 		spin_lock_irq(&scx_tasks_lock);
 	}
 	scx_task_iter_exit(&sti);
--
2.46.1

On Thu, Sep 26, 2024 at 03:30:12PM +0200, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Thu, 26 Sep 2024 14:51:07 +0200
> 
> A put_task_struct() call was immediately used after a return value check
> for a scx_ops_init_task() call in this function implementation.
> Thus call such a function only once instead directly before the check.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

This no longer applies after 9753358a6a2b ("sched_ext: Fix SCX_TASK_INIT ->
SCX_TASK_READY transitions in scx_ops_enable()").

Thanks.

-- 
tejun