6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nirmoy Das <nirmoy.das@xxxxxxxxx> [ Upstream commit 37a1cf288e4538eb39b38dbc745fe0da7ae53d94 ] If a previous ufence is not signalled, vm_bind will return -EBUSY. Delaying the modification of ufence->signalled can cause issues if the UMD reuses the same ufence so update ufence->signalled before waking up waiters. Cc: Matthew Brost <matthew.brost@xxxxxxxxx> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3233 Fixes: 977e5b82e090 ("drm/xe: Expose user fence from xe_sync_entry") Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20241114150537.4161573-1-nirmoy.das@xxxxxxxxx Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxxxx> (cherry picked from commit 553a5d14fcd927194c409b10faced6a6dbc678d1) Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/xe/xe_sync.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c index 2e72c06fd40d0..b0684e6d2047b 100644 --- a/drivers/gpu/drm/xe/xe_sync.c +++ b/drivers/gpu/drm/xe/xe_sync.c @@ -85,8 +85,12 @@ static void user_fence_worker(struct work_struct *w) mmput(ufence->mm); } - wake_up_all(&ufence->xe->ufence_wq); + /* + * Wake up waiters only after updating the ufence state, allowing the UMD + * to safely reuse the same ufence without encountering -EBUSY errors. + */ WRITE_ONCE(ufence->signalled, 1); + wake_up_all(&ufence->xe->ufence_wq); user_fence_put(ufence); } -- 2.43.0
