* Re: [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release
2025-09-19 16:43 [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release Adrián Larumbe
@ 2025-09-24 10:31 ` Steven Price
2025-09-25 8:20 ` Boris Brezillon
2025-09-25 8:56 ` Steven Price
2 siblings, 0 replies; 4+ messages in thread
From: Steven Price @ 2025-09-24 10:31 UTC (permalink / raw)
To: Adrián Larumbe, linux-kernel
Cc: dri-devel, Boris Brezillon, kernel, Liviu Dudau,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie,
Simona Vetter, Heiko Stuebner
On 19/09/2025 17:43, Adrián Larumbe wrote:
> Commit de8548813824 ("drm/panthor: Add the scheduler logical block")
> handled destruction of a group's queues' drm scheduler entities early
> into the group destruction procedure.
>
> However, that races with the group submit ioctl, because by the time
> entities are destroyed (through the group destroy ioctl), the submission
> procedure might've already obtained a group handle, and therefore the
> ability to push jobs into entities. This is met with a DRM error message
> within the drm scheduler core as a situation that should never occur.
>
> Fix by deferring drm scheduler entity destruction to queue release time.
>
> Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Looks good - I can't figure out why we had the early destruction, this
is more simple and safer.
Reviewed-by: Steven Price <steven.price@arm.com>
Thanks,
Steve
> ---
> drivers/gpu/drm/panthor/panthor_sched.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 0cc9055f4ee5..f5e01cb16cfc 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -898,8 +898,7 @@ static void group_free_queue(struct panthor_group *group, struct panthor_queue *
> if (IS_ERR_OR_NULL(queue))
> return;
>
> - if (queue->entity.fence_context)
> - drm_sched_entity_destroy(&queue->entity);
> + drm_sched_entity_destroy(&queue->entity);
>
> if (queue->scheduler.ops)
> drm_sched_fini(&queue->scheduler);
> @@ -3609,11 +3608,6 @@ int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle)
> if (!group)
> return -EINVAL;
>
> - for (u32 i = 0; i < group->queue_count; i++) {
> - if (group->queues[i])
> - drm_sched_entity_destroy(&group->queues[i]->entity);
> - }
> -
> mutex_lock(&sched->reset.lock);
> mutex_lock(&sched->lock);
> group->destroyed = true;
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release
2025-09-19 16:43 [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release Adrián Larumbe
2025-09-24 10:31 ` Steven Price
@ 2025-09-25 8:20 ` Boris Brezillon
2025-09-25 8:56 ` Steven Price
2 siblings, 0 replies; 4+ messages in thread
From: Boris Brezillon @ 2025-09-25 8:20 UTC (permalink / raw)
To: Adrián Larumbe
Cc: linux-kernel, dri-devel, Steven Price, kernel, Liviu Dudau,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie,
Simona Vetter, Heiko Stuebner
On Fri, 19 Sep 2025 17:43:48 +0100
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:
> Commit de8548813824 ("drm/panthor: Add the scheduler logical block")
> handled destruction of a group's queues' drm scheduler entities early
> into the group destruction procedure.
>
> However, that races with the group submit ioctl, because by the time
> entities are destroyed (through the group destroy ioctl), the submission
> procedure might've already obtained a group handle, and therefore the
> ability to push jobs into entities. This is met with a DRM error message
> within the drm scheduler core as a situation that should never occur.
>
> Fix by deferring drm scheduler entity destruction to queue release time.
>
> Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Discussed with you before you posted it, so here's the official
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Thanks for fixing that.
Boris
> ---
> drivers/gpu/drm/panthor/panthor_sched.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 0cc9055f4ee5..f5e01cb16cfc 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -898,8 +898,7 @@ static void group_free_queue(struct panthor_group *group, struct panthor_queue *
> if (IS_ERR_OR_NULL(queue))
> return;
>
> - if (queue->entity.fence_context)
> - drm_sched_entity_destroy(&queue->entity);
> + drm_sched_entity_destroy(&queue->entity);
>
> if (queue->scheduler.ops)
> drm_sched_fini(&queue->scheduler);
> @@ -3609,11 +3608,6 @@ int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle)
> if (!group)
> return -EINVAL;
>
> - for (u32 i = 0; i < group->queue_count; i++) {
> - if (group->queues[i])
> - drm_sched_entity_destroy(&group->queues[i]->entity);
> - }
> -
> mutex_lock(&sched->reset.lock);
> mutex_lock(&sched->lock);
> group->destroyed = true;
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release
2025-09-19 16:43 [PATCH] drm/panthor: Defer scheduler entitiy destruction to queue release Adrián Larumbe
2025-09-24 10:31 ` Steven Price
2025-09-25 8:20 ` Boris Brezillon
@ 2025-09-25 8:56 ` Steven Price
2 siblings, 0 replies; 4+ messages in thread
From: Steven Price @ 2025-09-25 8:56 UTC (permalink / raw)
To: Adrián Larumbe, linux-kernel
Cc: dri-devel, Boris Brezillon, kernel, Liviu Dudau,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie,
Simona Vetter, Heiko Stuebner
On 19/09/2025 17:43, Adrián Larumbe wrote:
> Commit de8548813824 ("drm/panthor: Add the scheduler logical block")
> handled destruction of a group's queues' drm scheduler entities early
> into the group destruction procedure.
>
> However, that races with the group submit ioctl, because by the time
> entities are destroyed (through the group destroy ioctl), the submission
> procedure might've already obtained a group handle, and therefore the
> ability to push jobs into entities. This is met with a DRM error message
> within the drm scheduler core as a situation that should never occur.
>
> Fix by deferring drm scheduler entity destruction to queue release time.
>
> Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Applied to drm-misc-fixes.
Thanks,
Steve
> ---
> drivers/gpu/drm/panthor/panthor_sched.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 0cc9055f4ee5..f5e01cb16cfc 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -898,8 +898,7 @@ static void group_free_queue(struct panthor_group *group, struct panthor_queue *
> if (IS_ERR_OR_NULL(queue))
> return;
>
> - if (queue->entity.fence_context)
> - drm_sched_entity_destroy(&queue->entity);
> + drm_sched_entity_destroy(&queue->entity);
>
> if (queue->scheduler.ops)
> drm_sched_fini(&queue->scheduler);
> @@ -3609,11 +3608,6 @@ int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle)
> if (!group)
> return -EINVAL;
>
> - for (u32 i = 0; i < group->queue_count; i++) {
> - if (group->queues[i])
> - drm_sched_entity_destroy(&group->queues[i]->entity);
> - }
> -
> mutex_lock(&sched->reset.lock);
> mutex_lock(&sched->lock);
> group->destroyed = true;
^ permalink raw reply [flat|nested] 4+ messages in thread