[PATCH] drm/syncobj: Fix oops on drm_syncobj_find_fence(file_priv, 0, ...).

[Eric Anholt]

This broke rendering on V3D, where we almost always have a 0
in-syncobj.

Signed-off-by: Eric Anholt <e...@anholt.net>
Fixes: 48197bc564c7 ("drm: add syncobj timeline support v9")
Cc: Chunming Zhou <david1.z...@amd.com>
Cc: Christian König <christian.koe...@amd.com>
---
 drivers/gpu/drm/drm_syncobj.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 4dca5f7e8c4b..da8175d9c6ff 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -443,7 +443,8 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
        int ret;
 
        ret = drm_syncobj_search_fence(syncobj, point, flags, fence);
-       drm_syncobj_put(syncobj);
+       if (syncobj)
+               drm_syncobj_put(syncobj);
        return ret;
 }
 EXPORT_SYMBOL(drm_syncobj_find_fence);
-- 
2.19.1