Am 31.07.21 um 10:04 schrieb Tuo Li:
The variable ttm is assigned to the variable gtt, and the variable gtt
is checked in:
if (gtt && gtt->userptr)
This indicates that both ttm and gtt can be NULL.
If so, a null-pointer dereference will occur:
if (ttm->page_flags & TTM_PAGE_FLAG_SG)
Also, some null-pointer dereferences will occur in the function
ttm_pool_alloc() which is called in:
return ttm_pool_alloc(&adev->mman.bdev.pool, ttm, ctx);
To fix these possible null-pointer dereferences, the function returns
-EINVAL when ttm is NULL.
NAK, the NULL test is just a leftover from when the objects where distinct.
Please remove the NULL test instead.
Regards,
Christian.
Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>
Signed-off-by: Tuo Li <islituo@xxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 3a55f08e00e1..80440f799c09 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1120,8 +1120,11 @@ static int amdgpu_ttm_tt_populate(struct ttm_device *bdev,
struct amdgpu_device *adev = amdgpu_ttm_adev(bdev);
struct amdgpu_ttm_tt *gtt = (void *)ttm;
+ if (ttm == NULL)
+ return -EINVAL;
+
/* user pages are bound by amdgpu_ttm_tt_pin_userptr() */
- if (gtt && gtt->userptr) {
+ if (gtt->userptr) {
ttm->sg = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
if (!ttm->sg)
return -ENOMEM;
