From: Jakob Bornecrantz <jakob@vmware.com>
Date: Wed, 30 Oct 2013 09:46:56 +0000 (-0700)
Subject: drm/ttm: Handle in-memory region copies
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9a0599ddeae012a771bba5e23393fc52d8a59d89;p=linux-beck.git

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 7cc904d3a4d1..8369e35c0dce 100644
--- 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