On Mon, Mar 12, 2018 at 4:17 PM, Cong Wang <xiyou.wangc...@gmail.com> wrote: > On Sun, Mar 11, 2018 at 12:22 PM, Josh Elsasser <jelsas...@appneta.com> wrote: >> init_dummy_netdev() leaves its netdev_ops pointer zeroed. This leads >> to a NULL pointer dereference when sk_busy_loop fires against an iwlwifi >> wireless adapter and checks napi->dev->netdev_ops->ndo_busy_poll. >> >> Avoid this by ensuring that napi->dev is not a dummy device before >> dereferencing napi dev's netdev_ops, preventing the following panic: > > Hmm, how about just checking ->netdev_ops? Checking reg_state looks > odd, although works.
Fair point. I was trying to differentiate between an unexpected NULL pointer and a dummy netdev, but I guess it was clever at the expense of readability. I'll push up a v2 that just does the obvious.