Messages in this thread | | | Subject | Re: [PATCH] drm/amdgpu: fix possible null-pointer dereference in amdgpu_ttm_tt_populate() | From | Christian König <> | Date | Sun, 1 Aug 2021 19:19:03 +0200 |
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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@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..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;
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