Am 31.12.21 um 09:37 schrieb 温志伟:

Then the judgment in line 944 is needed. Are the possibilities of these two positions consistent.

Why keep this judgment？

Because when mem is non-NULL bo_va->bo can't be NULL either.

Regards, Christian.

Regards,

Wen Zhiwei.

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*主　题：*Re: [PATCH] gpu/drm/radeon:Fix null pointer risk *日　期：*2021-12-31 00:36 *发件人：*Christian König *收件人：*Wen Zhiweialexander.deucher@amd.comXinhui.Pan@amd.comairlied@linux.iedaniel@ffwll.ch

Am 28.12.21 um 08:31 schrieb Wen Zhiwei:

...

If the null pointer is not judged in advance, there is a risk that the pointer will cross the boundary

As far as I can see that case is impossible, why do you want to add a check for it?

Regards, Christian.

...

Signed-off-by: Wen Zhiwei

drivers/gpu/drm/radeon/radeon_vm.c | 2 +-   1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_vm.c

b/drivers/gpu/drm/radeon/radeon_vm.c

...

index bb53016f3138..d3d342041adf 100644 --- a/drivers/gpu/drm/radeon/radeon_vm.c +++ b/drivers/gpu/drm/radeon/radeon_vm.c @@ -951,7 +951,7 @@ int radeon_vm_bo_update(struct radeon_device *rdev,

if (mem->mem_type == TTM_PL_TT) {   bo_va->flags |= RADEON_VM_PAGE_SYSTEM;

• if (!(bo_va->bo->flags & (RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC)))

• if (bo_va->bo && !(bo_va->bo->flags & (RADEON_GEM_GTT_WC |

RADEON_GEM_GTT_UC)))

...

bo_va->flags |= RADEON_VM_PAGE_SNOOPED;

} else {