Re: net: check before dereferencing netdev_ops during busy poll

From: Matteo Croce <mcroce@redhat.com>
To: Josh Elsasser <jelsasser@appneta.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>,
	stable@vger.kernel.org, netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	David Miller <davem@davemloft.net>
Subject: Re: net: check before dereferencing netdev_ops during busy poll
Date: Mon, 1 Jul 2019 20:03:28 +0200	[thread overview]
Message-ID: <CAGnkfhx3ykbEsW+=FtpMFWU=_Vnie7RpPYWpWqa1S1HPMXj9kw@mail.gmail.com> (raw)
In-Reply-To: <20190701175241.GB9081@kroah.com>

On Mon, Jul 1, 2019 at 7:53 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> 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@linuxfoundation.org> 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@kernel.org> 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@davemloft.net/
> >
> > Anyway, I tested the patch and it fixes the panic, at least on my
> > iwlwifi card, so:
> >
> > Tested-by: Matteo Croce <mcroce@redhat.com>
>
> 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

Understood.

Josh, as you are the original author, can you please resend it to -stable?
Feel free to add this tag:

Tested-by: Matteo Croce <mcroce@redhat.com>

Regards,
-- 
Matteo Croce
per aspera ad upstream