"Gustavo A. R. Silva" [off-list ref] writes:

On Mon, Oct 18, 2021 at 02:09:31PM -0700, Tyrel Datwyler wrote:

quoted

On 10/14/21 10:03 PM, Gustavo A. R. Silva wrote:

quoted

(!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.

I've already put it in powerpc/next:

  https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36

If you need to pick it up as well for some reason that's fine.

cheers