Message-ID: <1498801985.24896.4.camel@haakon3.risingtidesystems.com>
Subject: Re: [PATCH] ib_isert: prevent NULL pointer dereference in
 isert_login_recv_done()
From: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Andrea Righi <righi.andrea@gmail.com>,
        Robert LeBlanc <robert@leblancnet.us>,
        Sean Jenkins <sean@betterservers.com>,
        Doug Ledford <dledford@redhat.com>, Sean Hefty <sean.hefty@intel.com>,
        Hal Rosenstock <hal.rosenstock@gmail.com>,
        linux-rdma <linux-rdma@vger.kernel.org>,
        target-devel <target-devel@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>, Christoph Hellwig <hch@lst.de>
Date: Thu, 29 Jun 2017 22:53:05 -0700
In-Reply-To: <7f1b1f07-0670-10ee-620d-0ab3b1a6c2bf@grimberg.me>
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On Thu, 2017-06-29 at 11:28 +0300, Sagi Grimberg wrote:
> >> Can you test just the one liner fix below?
> >>
> >>>> @@ -1452,7 +1452,7 @@
> >>>>   isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc)
> >>>>   {
> >>>>   	struct isert_conn *isert_conn = wc->qp->qp_context;
> >>>> -	struct ib_device *ib_dev = isert_conn->cm_id->device;
> >>>> +	struct ib_device *ib_dev = isert_conn->device->ib_device;
> >>>>   	if (unlikely(wc->status != IB_WC_SUCCESS)) {
> >>>>   		isert_print_wc(wc, "login recv");
> > 
> > I'll test also this one-liner fix as soon as I can.
> > 
> > But I can say that I'm pretty sure it will work as well, because all the
> > previous NULL pointer dereferences that we've got in the past happened
> > all 100% in isert_login_recv_done(). The other cases are probably a safe
> > precaution, but they can't really happen.
> 
> Agree, I'd prefer to start with a surgical fix before moving forward.

Sounds fine.  The single line fix above in isert_login_recv_done() has
been queued up in target-pending/for-next with Andrea's Tested-by and
your Reviewed-by:

https://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending.git/commit/?h=for-next&id=702c0f17403765cc5aa1c18f6ea6eb549c1bac9b

Please let me know if there are any other issues wrt the surgical fix.