Linaro-mm-sig August 2021

linaro-mm-sig@lists.linaro.org

15 participants
43 discussions

Re: [Linaro-mm-sig] [PATCH] drm/amdgpu: drop redundant null-pointer checks in amdgpu_ttm_tt_populate() and amdgpu_ttm_tt_unpopulate()

by Christian König

Am 04.08.21 um 03:51 schrieb Tuo Li: > The varialbe gtt in the function amdgpu_ttm_tt_populate() and > amdgpu_ttm_tt_unpopulate() is guaranteed to be not NULL in the context. > Thus the null-pointer checks are redundant and can be dropped. > > Reported-by: TOTE Robot <oslab(a)tsinghua.edu.cn> > Signed-off-by: Tuo Li <islituo(a)gmail.com> Reviewed-by: Christian König <christian.koenig(a)amd.com> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > index 3a55f08e00e1..719539bd6c44 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > @@ -1121,7 +1121,7 @@ static int amdgpu_ttm_tt_populate(struct ttm_device *bdev, > struct amdgpu_ttm_tt *gtt = (void *)ttm; > > /* 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; > @@ -1146,7 +1146,7 @@ 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 (gtt->userptr) { > amdgpu_ttm_tt_set_user_pages(ttm, NULL); > kfree(ttm->sg); > ttm->sg = NULL;

3 years, 4 months

Re: [Linaro-mm-sig] [PATCH] drm/amdgpu: fix possible null-pointer dereference in amdgpu_ttm_tt_unpopulate()

by Christian König

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(a)tsinghua.edu.cn> > Signed-off-by: Tuo Li <islituo(a)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;

3 years, 4 months

Re: [Linaro-mm-sig] [PATCH] drm/amdgpu: fix possible null-pointer dereference in amdgpu_ttm_tt_populate()

by Christian König

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(a)tsinghua.edu.cn> > Signed-off-by: Tuo Li <islituo(a)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;

3 years, 4 months

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Linaro-mm-sig August 2021