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Date:   Thu, 28 Mar 2019 09:40:37 -0300
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Potnuri Bharat Teja <bharat@chelsio.com>
Cc:     Kangjie Lu <kjlu@umn.edu>, "pakki001@umn.edu" <pakki001@umn.edu>,
        Doug Ledford <dledford@redhat.com>,
        "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: <20190328124037.GJ21008@ziepe.ca>
References: <20190309051921.15212-1-kjlu@umn.edu>
 <CC1E06D8-7817-4314-AAD4-434FEB8C4157@umn.edu>
 <20190327133728.GA26660@chelsio.com>
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On Wed, Mar 27, 2019 at 07:08:54PM +0530, Potnuri Bharat Teja wrote:
> 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
> > > +++ 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;
> }

no error prints on memory allocation failure, the kernel already
prints enough on this

Jason