Subject: Re: [PATCH] ib_isert: prevent NULL pointer dereference in
 isert_login_recv_done()
To: Andrea Righi <righi.andrea@gmail.com>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>,
        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>
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 <20170622223757.GC28955@Dell>
 <1498435084.26123.66.camel@haakon3.risingtidesystems.com>
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 <ac404f71-3f34-af4c-b7b2-2b19ae768f47@grimberg.me>
 <20170629082057.GA2037@Dell>
From: Sagi Grimberg <sagi@grimberg.me>
Message-ID: <7f1b1f07-0670-10ee-620d-0ab3b1a6c2bf@grimberg.me>
Date: Thu, 29 Jun 2017 11:28:40 +0300
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>> 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.