Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod
From: Andrea Righi <righi.andrea@gmail.com>
Newsgroups: linux.kernel
Subject: Re: [PATCH] ib_isert: prevent NULL pointer dereference in  isert_login_recv_done()
Date: Thu, 29 Jun 2017 10:30:01 +0200
Message-ID: <tXCZP-5df-5@gated-at.bofh.it>
References: <tViVA-2hN-19@gated-at.bofh.it> <tViVA-2hN-21@gated-at.bofh.it> <tViVA-2hN-23@gated-at.bofh.it> <tViVA-2hN-17@gated-at.bofh.it> <tWpBE-38C-5@gated-at.bofh.it> <tXpq5-t5-223@gated-at.bofh.it> <tXAlk-3x9-5@gated-at.bofh.it>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: robomod@news.nic.it
Approved: robomod@news.nic.it
Lines: 26
Organization: linux.* mail to news gateway
Xref: csiph.com linux.kernel:1677514

On Thu, Jun 29, 2017 at 08:36:51AM +0300, Sagi Grimberg wrote:
> 
> >Just tested this patch, I wasn't able to reproduce the NULL pointer
> >dereference or any other bugs, so this fix seems safe enough to me.
> >
> >Tested-by: Andrea Righi <righi.andrea@gmail.com>
> 
> 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.

-Andrea