Re: [PATCH][next] powerpc/vas: Fix potential NULL pointer dereference

Gustavo A. R. Silva
2021-10-26T18:37:12Z

On Mon, Oct 18, 2021 at 02:09:31PM -0700, Tyrel Datwyler wrote:
> On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:
> > (!ptr && !ptr->foo) strikes again. :)
> >
> > The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
> > it leads to a NULL pointer dereference: ptr->foo.
> >
> > Fix this by converting && to ||
> >
> > This issue was detected with the help of Coccinelle, and audited and
> > fixed manually.
> >
> > Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> Looking at the usage pattern it is obvious that if we determine !ptr attempting
> to also confirm !ptr->ops is going to blow up.
>
> LGTM.
>
> Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>

I think I'll take this in my tree.

Thanks, Tyrel.
--
Gustavo