[PATCH] drm/scheduler: Fix mem leak when last_scheduled signaled
Philipp Stanner
phasta at mailbox.org
Mon Feb 24 09:52:56 UTC 2025
Hello,
subject line: please write "drm/sched" instead of "drm/scheduler". It
has become the norm
On Fri, 2025-02-21 at 14:27 +0800, qianyi liu wrote:
> Problem: If prev(last_scheduled) was already signaled I encountred a
prev(last_scheduled) almost reads like a function call. Maybe write
"prev / last_scheduled"?
> memory leak in drm_sched_entity_fini. This is because the
> prev(last_scheduled) fence is not free properly.
s/free/freed
>
> Fix: Balance the prev(last_scheduled) fence refcnt when
> dma_fence_add_callback failed.
>
> Signed-off-by: qianyi liu <liuqianyi125 at gmail.com>
> ---
> drivers/gpu/drm/scheduler/sched_entity.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c
> b/drivers/gpu/drm/scheduler/sched_entity.c
> index 69bcf0e99d57..1c0c14bcf726 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -259,9 +259,12 @@ static void drm_sched_entity_kill(struct
> drm_sched_entity *entity)
> struct drm_sched_fence *s_fence = job->s_fence;
>
> dma_fence_get(&s_fence->finished);
> - if (!prev || dma_fence_add_callback(prev, &job-
> >finish_cb,
> -
> drm_sched_entity_kill_jobs_cb))
> + if (!prev ||
> + dma_fence_add_callback(prev, &job->finish_cb,
> +
> drm_sched_entity_kill_jobs_cb)) {
> + dma_fence_put(prev);
But now the fence will also be put when prev == NULL. Is that
intentional? It doesn't seem correct to me from looking at the commit
message, which states "Balance […] refcnt when dma_fence_add_callback
failed"
It didn't get clear to me immediately which dma_fence_get() your new
dma_fence_put() balances. Can you ellaborate on that or maybe write a
comment?
But also be handy of could share the kmemleak trace.
Thanks
P.
> drm_sched_entity_kill_jobs_cb(NULL, &job-
> >finish_cb);
> + }
>
> prev = &s_fence->finished;
> }
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