drm-misc-fixes doesn't have the updated ttm_bo.c file, we have the updated ttm_bo.c version in
drm-misc-next branch. Please find below for the line number 907.
On 8/11/2022 3:25 PM, Dan Carpenter
wrote:
Hello Arunpravin Paneer Selvam,
This is a semi-automatic email about new static checker warnings.
The patch cf4b7387c0a8: "drm/ttm: Fix dummy res NULL ptr deref bug"
from Aug 9, 2022, leads to the following Smatch complaint:
drivers/gpu/drm/ttm/ttm_bo.c:915 ttm_bo_validate()
warn: variable dereferenced before check 'bo->resource' (see line 907)
drivers/gpu/drm/ttm/ttm_bo.c
906 */
907 if (!ttm_resource_compat(bo->resource, placement)) {
^^^^^^^^^^^^
Unchecked dereference here inside the function.
if (!bo->resource || !ttm_resource_compat(bo->resource, placement)) {
we have this version in drm-misc-next
Regards,
Arun
908 ret = ttm_bo_move_buffer(bo, placement, ctx);
909 if (ret)
910 return ret;
911 }
912 /*
913 * We might need to add a TTM.
914 */
915 if (!bo->resource || bo->resource->mem_type == TTM_PL_SYSTEM) {
^^^^^^^^^^^^
Checked too late.
This NULL check was added deliberately based on a report from the kbuild
bot, but it's not clear why bo->resource is NULL at this point. Was the
patch tested? There is a stable@xxxxxxxxxxxxxxx but there is no Fixes
tag.
916 ret = ttm_tt_create(bo, true);
917 if (ret)
regards,
dan carpenter
