Re: 回复: Re: [PATCH] gpu/drm/radeon:Fix null pointer risk

[Christian König]

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.
>
>
> ----
>
>
>
>
>
> *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 at amd.comXinhui.Pan@amd.comairlied at 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 {
>

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