Re: [PATCH 4.19 1/1] drm/amdkfd: Check for null pointer after calling kmemdup

[Christian König]

Am 04.01.23 um 13:41 schrieb Greg KH:
> On Tue, Jan 03, 2023 at 08:43:08PM +0200, Dragos-Marian Panait wrote:
> > From: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
> >
> > [ Upstream commit abfaf0eee97925905e742aa3b0b72e04a918fa9e ]
> >
> > As the possible failure of the allocation, kmemdup() may return NULL
> > pointer.
> > Therefore, it should be better to check the 'props2' in order to prevent
> > the dereference of NULL pointer.
> >
> > Fixes: 3a87177eb141 ("drm/amdkfd: Add topology support for dGPUs")
> > Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
> > Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> > Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> > Signed-off-by: Dragos-Marian Panait <dragos.panait@xxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 3 +++
> >   1 file changed, 3 insertions(+)
> For obvious reasons, I can't take a patch for 4.19.y and not newer
> kernel releases, right?
>
> Please provide backports for all kernels if you really need to see this
> merged.  And note, it's not a real bug at all, and given that a CVE was
> allocated for it that makes me want to even more reject it to show the
> whole folly of that mess.

Well as far as I can see this is nonsense to back port.

The code in question is only used only once during driver load and then 
never again, that exactly this allocation fails while tons of other are 
made before and after is extremely unlikely.

It's nice to have it fixed in newer kernels, but not worth a backport 
and certainly not stuff for a CVE.

Regards,
Christian.


> thanks,
>
> greg k-h