From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Date: Mon, 08 May 2017 17:44:03 +0000 Subject: Re: [PATCH] net: dsa: loop: Check for memory allocation failure Message-Id: <1494265443.31950.62.camel@perches.com> List-Id: References: <20170506052945.2639-1-christophe.jaillet@wanadoo.fr> <063D6719AE5E284EB5DD2968C1650D6DCFFE715E@AcuExch.aculab.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Julia Lawall , David Laight Cc: 'Christophe JAILLET' , "andrew@lunn.ch" , "vivien.didelot@savoirfairelinux.com" , "f.fainelli@gmail.com" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kernel-janitors@vger.kernel.org" On Mon, 2017-05-08 at 20:32 +0800, Julia Lawall wrote: > > On Mon, 8 May 2017, David Laight wrote: > > > From: Christophe JAILLET > > > Sent: 06 May 2017 06:30 > > > If 'devm_kzalloc' fails, a NULL pointer will be dereferenced. > > > Return -ENOMEM instead, as done for some other memory allocation just a > > > few lines above. > > > > ... > > > --- a/drivers/net/dsa/dsa_loop.c > > > +++ b/drivers/net/dsa/dsa_loop.c > > > @@ -256,6 +256,9 @@ static int dsa_loop_drv_probe(struct mdio_device *mdiodev) > > > return -ENOMEM; > > > > > > ps = devm_kzalloc(&mdiodev->dev, sizeof(*ps), GFP_KERNEL); > > > + if (!ps) > > > + return -ENOMEM; > > > + > > > ps->netdev = dev_get_by_name(&init_net, pdata->netdev); > > > if (!ps->netdev) > > > return -EPROBE_DEFER; > > > > On the face if it this code leaks like a sieve. > > I don't think so. The allocations (dsa_switch_alloc and devm_kzalloc) use > devm functions. It's at least wasteful. Each time -EPROBE_DEFER occurs, another set of calls to dsa_switch_alloc and dev_kzalloc also occurs. Perhaps it'd be better to do: if (ps->netdev) { devm_kfree(&devmdev->dev, ps); devm_kfree(&mdiodev->dev, ds); return -EPROBE_DEFER; }