Re: net: check before dereferencing netdev_ops during busy poll

[Greg Kroah-Hartman]

On Sat, Jun 29, 2019 at 09:39:39PM +0200, Matteo Croce wrote:
> On Sat, Jun 29, 2019 at 9:45 AM Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Fri, Jun 28, 2019 at 07:03:01PM -0700, Josh Elsasser wrote:
> > > On Jun 28, 2019, at 3:55 PM, Sasha Levin <sashal@xxxxxxxxxx> wrote:
> > >
> > > > What's the upstream commit id?
> > >
> > > The commit wasn't needed upstream, as I only sent the original patch after
> > > 79e7fff47b7b ("net: remove support for per driver ndo_busy_poll()") had
> > > made the fix unnecessary in Linus' tree.
> > >
> > > May've gotten lost in the shuffle due to my poor Fixes tags. The patch in
> > > question applied only on top of the 4.9 stable release at the time, but the
> > > actual NPE had been around in some form since 3.11 / 0602129286705 ("net: add
> > > low latency socket poll").
> >
> > Ok, can people then resend this and be very explicit as to why this is
> > needed only in a stable kernel tree and get reviews from people agreeing
> > that this really is the correct fix?
> >
> > thanks,
> >
> > greg k-h
> 
> Hi Greg,
> 
> I think that David alredy reviewed the patch here:
> 
> https://lore.kernel.org/netdev/20180313.105115.682846171057663636.davem@xxxxxxxxxxxxx/
> 
> Anyway, I tested the patch and it fixes the panic, at least on my
> iwlwifi card, so:
> 
> Tested-by: Matteo Croce <mcroce@xxxxxxxxxx>

Ok, but what can I do with this?  I need a real patch, in mail form,
that I can apply.  Not a web link to an email archive.

You have read the stable kernel rules, right?  :)

greg k-h