| Message ID | 20210731081306.86523-1-islituo@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | drm/amdgpu: fix possible null-pointer dereference in amdgpu_ttm_tt_unpopulate() | expand |
Am 31.07.21 um 10:13 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_free() which is called in: > return ttm_pool_free(&adev->mman.bdev.pool, ttm); > > To fix these possible null-pointer dereferences, the function returns > when ttm is NULL. NAK, same as with the other patch. The ttm object is mandatory, asking the driver to destroy a ttm object which doesn't exists makes no sense at all and is a bug in the upper layer. The NULL check is just a leftover from when the gtt and ttm objects where distinct. Please remove that one instead. BTW: Bonus points for changing the (void *) cast into a much cleaner container_of(). Thanks, Christian. > > Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> > Signed-off-by: Tuo Li <islituo@gmail.com> > --- > 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..0216ca085f11 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > @@ -1146,7 +1146,10 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_device *bdev, > struct amdgpu_ttm_tt *gtt = (void *)ttm; > struct amdgpu_device *adev; > > - if (gtt && gtt->userptr) { > + if (ttm == NULL) > + return; > + > + if (gtt->userptr) { > amdgpu_ttm_tt_set_user_pages(ttm, NULL); > kfree(ttm->sg); > ttm->sg = NULL;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 3a55f08e00e1..0216ca085f11 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -1146,7 +1146,10 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_device *bdev, struct amdgpu_ttm_tt *gtt = (void *)ttm; struct amdgpu_device *adev; - if (gtt && gtt->userptr) { + if (ttm == NULL) + return; + + if (gtt->userptr) { amdgpu_ttm_tt_set_user_pages(ttm, NULL); kfree(ttm->sg); ttm->sg = NULL;
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_free() which is called in: return ttm_pool_free(&adev->mman.bdev.pool, ttm); To fix these possible null-pointer dereferences, the function returns when ttm is NULL. Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Tuo Li <islituo@gmail.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)