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Date:   Wed, 27 Mar 2019 19:08:54 +0530
From:   Potnuri Bharat Teja <bharat@chelsio.com>
To:     Kangjie Lu <kjlu@umn.edu>
Cc:     "pakki001@umn.edu" <pakki001@umn.edu>,
        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] infiniband: cxgb4: fix a potential NULL pointer
 dereference
Message-ID: <20190327133728.GA26660@chelsio.com>
References: <20190309051921.15212-1-kjlu@umn.edu>
 <CC1E06D8-7817-4314-AAD4-434FEB8C4157@umn.edu>
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On Saturday, March 03/23/19, 2019 at 08:07:46 +0530, Kangjie Lu wrote:
> 
> 
> > On Mar 8, 2019, at 11:19 PM, Kangjie Lu <kjlu@umn.edu> wrote:
> > 
> > get_skb may fail and return NULL. The fix returns "ENOMEM"
> > when it fails to avoid NULL dereference.
> > 
> > Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> > ---
> > drivers/infiniband/hw/cxgb4/cm.c | 3 +++
> > 1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
> > index 8221813219e5..502a54d57e2c 100644
> > --- a/drivers/infiniband/hw/cxgb4/cm.c
> > +++ b/drivers/infiniband/hw/cxgb4/cm.c
> > @@ -1919,6 +1919,9 @@ static int send_fw_act_open_req(struct c4iw_ep *ep, unsigned int atid)
> > 	int win;
> > 
> > 	skb = get_skb(NULL, sizeof(*req), GFP_KERNEL);
> > +	if (!skb)
> > +		return -ENOMEM;
> > +
> 
> Can someone review this patch? Thanks.

Sorry for the late response.
I recommend an error print before the return.
---
if (!skb) {
	pr_err("%s - failed to alloc skb\n", __func__);
	return -ENOMEM;
}
---
Thanks for the patch!
- Bharat.
> 
> > 	req = __skb_put_zero(skb, sizeof(*req));
> > 	req->op_compl = htonl(WR_OP_V(FW_OFLD_CONNECTION_WR));
> > 	req->len16_pkd = htonl(FW_WR_LEN16_V(DIV_ROUND_UP(sizeof(*req), 16)));
> > -- 
> > 2.17.1
> > 
>