From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Mc Guire Subject: Re: [PATCH] gpio: mt7621: handle failure of devm_kasprintf() Date: Wed, 21 Nov 2018 18:01:16 +0100 Message-ID: <20181121170116.GA10656@osadl.at> References: <1542818142-27800-1-git-send-email-hofrat@osadl.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Bartosz Golaszewski Cc: linux-gpio , Linus Walleij , LKML , sergio.paracuellos@gmail.com, linux-mediatek@lists.infradead.org, hofrat@osadl.org, matthias.bgg@gmail.com, arm-soc List-Id: linux-gpio@vger.kernel.org On Wed, Nov 21, 2018 at 05:43:43PM +0100, Bartosz Golaszewski wrote: > ??r., 21 lis 2018 o 17:39 Nicholas Mc Guire napisa??(a= ): > > > > kasprintf() may return NULL on failure of internal allocation thus the > > assigned label is not safe if not explicitly checked. On error > > mediatek_gpio_bank_probe() returns negative values so -ENOMEM in the > > (unlikely) failure case should be fine here. > > > > Signed-off-by: Nicholas Mc Guire > > Fixes: 4ba9c3afda41 ("gpio: mt7621: Add a driver for MT7621") > > --- > > > > Problem located with experimental coccinelle script > > > > Patch was compile tested with: omega2p_defconfig, SOC_MT7621=3Dy, > > GPIOLIB=3Dy, GPIO_MT7621=3Dy > > > > Patch is against 4.20-rc3 (localversion-next is next-20181121) > > > > drivers/gpio/gpio-mt7621.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpio/gpio-mt7621.c b/drivers/gpio/gpio-mt7621.c > > index d72af6f..42f0c67 100644 > > --- a/drivers/gpio/gpio-mt7621.c > > +++ b/drivers/gpio/gpio-mt7621.c > > @@ -244,6 +244,10 @@ mediatek_gpio_bank_probe(struct device *dev, > > rg->chip.of_xlate =3D mediatek_gpio_xlate; > > rg->chip.label =3D devm_kasprintf(dev, GFP_KERNEL, "%s-bank%d", > > dev_name(dev), bank); > > + if (!rg->chip.label) { > > + dev_err(dev, "Could not allocate label\n"); > = > No need for an error message here, an -ENOMEM says enough. > I just thought its more consistent with the rest of the code - and as it is a highly unlikely event it would probably be hard to pinpoint as some of the other functions can return -ENOMEM (but with a message). ....and the call site of mediatek_gpio_bank_probe() actually = currently ignores the return value so the -ENOMEM would go unnoticed which is a bug as well - patch for that a bit later. anyway fine with me - I=B4ll send a V2 and drop the dev_err() here. thx! hofrat = > Bart > = > > + return -ENOMEM; > > + } > > > > ret =3D devm_gpiochip_add_data(dev, &rg->chip, mtk); > > if (ret < 0) { > > -- > > 2.1.4 > >