[PATCH] drm/ttm: request zeroed system memory pages for new TT buffer objects

[skeggsb at gmail.com]

From: Ben Skeggs <bskeggs at redhat.com>

Fixes an information leak to userspace, we were handing out un-zeroed pages
for any newly created TTM_PL_TT buffer.

Reported-by: Marcin Slusarz <marcin.slusarz at gmail.com>
Signed-off-by: Ben Skeggs <bskeggs at redhat.com>
Tested-by: Marcin Slusarz <marcin.slusarz at gmail.com>
Cc: stable at kernel.org
---
 drivers/gpu/drm/ttm/ttm_bo.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index a4d38d8..ef06194 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -394,7 +394,8 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 
 	if (!(new_man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
 		if (bo->ttm == NULL) {
-			ret = ttm_bo_add_ttm(bo, false);
+			bool zero = !(old_man->flags & TTM_MEMTYPE_FLAG_FIXED);
+			ret = ttm_bo_add_ttm(bo, zero);
 			if (ret)
 				goto out_err;
 		}
-- 
1.7.6.1