drm/ttm: Handle in-memory region copies

Fix the case where the ttm pointer may be NULL causing
a NULL pointer dereference.

Signed-off-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Thomas Hellström <thellstrom@vmware.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 7cc904d3a4d12b4efd6935f75ed302335552a4aa..8369e35c0dce744933331636cdd680b04f66b39f 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -348,7 +348,9 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
        if (old_iomap == NULL && ttm == NULL)
                goto out2;
 
-       if (ttm->state == tt_unpopulated) {
+       /* TTM might be null for moves within the same region.
+        */
+       if (ttm && ttm->state == tt_unpopulated) {
                ret = ttm->bdev->driver->ttm_tt_populate(ttm);
                if (ret) {
                        /* if we fail here don't nuke the mm node