[Intel-wired-lan] [next-queue PATCH v2 2/5] net/sched: Fix accessing invalid dev_queue

[Cong Wang]

On Fri, Sep 29, 2017 at 5:26 PM, Vinicius Costa Gomes
<vinicius.gomes at intel.com> wrote:
> From: Jesus Sanchez-Palencia <jesus.sanchez-palencia at intel.com>
>
> In qdisc_alloc() the dev_queue pointer was used without any checks being
> performed. If qdisc_create() gets a null dev_queue pointer, it just
> passes it along to qdisc_alloc(), leading to a crash. That happens if a
> root qdisc implements select_queue() and returns a null dev_queue
> pointer for an "invalid handle", for example.

Does it make sense to let mqprio_select_queue() always return
non-NULL?

At least mq_select_queue() returns queue #0 as a fallback.