drm/ttm: Fix a sync object leak.

If there are multiple simultaneous waiters for the same buffer object,
a temporary reference to its sync object may be leaked.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 6538d4236989..aa82d5370c38 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1575,6 +1575,10 @@ int ttm_bo_wait(struct ttm_buffer_object *bo,
                         driver->sync_obj_unref(&sync_obj);
                         driver->sync_obj_unref(&tmp_obj);
                         spin_lock(&bo->lock);
+                } else {
+                        spin_unlock(&bo->lock);
+                        driver->sync_obj_unref(&sync_obj);
+                        spin_lock(&bo->lock);
                 }
         }
         return 0;