2021-02-06 20:54:19

by Tom Rix

Subject: [PATCH] sched/deadline: fix BUG_ON() ENQUEUE_REPLENISH check

From: Tom Rix <[email protected]>

When the BUG_ON check for (flags != ENQUEUE_REPLENISH) was created, the
flag was set to ENQUEUE_REPLENISH in rt_mutex_setprio(), now it is or-ed
in. So the checking logic needs to change.

Fixes: 1de64443d755 ("sched/core: Fix task and run queue sched_info::run_delay inconsistencies")
Signed-off-by: Tom Rix <[email protected]>
---
kernel/sched/deadline.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 1508d126e88b..f50d20b7fe7c 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1561,7 +1561,7 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
* the throttle.
*/
p->dl.dl_throttled = 0;
- BUG_ON(!is_dl_boosted(&p->dl) || flags != ENQUEUE_REPLENISH);
+ BUG_ON(!is_dl_boosted(&p->dl) || !(flags & ENQUEUE_REPLENISH));
return;
}

--
2.27.0

2021-02-08 10:56:05

by Juri Lelli

Subject: Re: [PATCH] sched/deadline: fix BUG_ON() ENQUEUE_REPLENISH check

Hi,

On 06/02/21 12:48, [email protected] wrote:
> From: Tom Rix <[email protected]>
>
> When the BUG_ON check for (flags != ENQUEUE_REPLENISH) was created, the
> flag was set to ENQUEUE_REPLENISH in rt_mutex_setprio(), now it is or-ed
> in. So the checking logic needs to change.
>
> Fixes: 1de64443d755 ("sched/core: Fix task and run queue sched_info::run_delay inconsistencies")
> Signed-off-by: Tom Rix <[email protected]>
> ---
> kernel/sched/deadline.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 1508d126e88b..f50d20b7fe7c 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1561,7 +1561,7 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
> * the throttle.
> */
> p->dl.dl_throttled = 0;
> - BUG_ON(!is_dl_boosted(&p->dl) || flags != ENQUEUE_REPLENISH);
> + BUG_ON(!is_dl_boosted(&p->dl) || !(flags & ENQUEUE_REPLENISH));

Uhu, isn't this actually the else branch of "if (is_dl_boosted())"? If
yes, I don't see how this is not always triggering. :-/

Thanks,
Juri