Re: [PATCH v2] Revert "drm/nouveau: Remove waitque for sched teardown"

[Danilo Krummrich]

On Mon Sep 1, 2025 at 10:31 AM CEST, Philipp Stanner wrote:
> This reverts:
>
> commit bead88002227 ("drm/nouveau: Remove waitque for sched teardown")
> commit 5f46f5c7af8c ("drm/nouveau: Add new callback for scheduler teardown")
>
> from the drm/sched teardown leak fix series:
>
> https://lore.kernel.org/dri-devel/20250710125412.128476-2-phasta@xxxxxxxxxx/
>
> The aforementioned series removed a blocking waitqueue from
> nouveau_sched_fini(). It was mistakenly assumed that this waitqueue only
> prevents jobs from leaking, which the series fixed.
>
> The waitqueue, however, also guarantees that all VM_BIND related jobs
> are finished in order, cleaning up mappings in the GPU's MMU. These jobs
> must be executed sequentially. Without the waitqueue, this is no longer
> guaranteed, because entity and scheduler teardown can race with each
> other.
>
> Revert all patches related to the waitqueue removal.
>
> Fixes: bead88002227 ("drm/nouveau: Remove waitque for sched teardown")
> Suggested-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> Signed-off-by: Philipp Stanner <phasta@xxxxxxxxxx>

Applied to drm-misc-fixes, thanks!