From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Date: Mon, 31 May 2010 19:17:23 +0000 Subject: Re: [patch 1/2] input/tps6507x-ts: dereferencing before checking Message-Id: <20100531191723.GE30712@core.coreip.homeip.net> List-Id: References: <20100531120122.GR5483@bicker> In-Reply-To: <20100531120122.GR5483@bicker> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dan Carpenter Cc: Todd Fischer , Samuel Ortiz , linux-input@vger.kernel.org, kernel-janitors@vger.kernel.org On Mon, May 31, 2010 at 02:01:22PM +0200, Dan Carpenter wrote: > This patch moves the dereference after the check for NULL. > > Signed-off-by: Dan Carpenter > > diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c > index 5de80a1..b99db09 100644 > --- a/drivers/input/touchscreen/tps6507x-ts.c > +++ b/drivers/input/touchscreen/tps6507x-ts.c > @@ -355,10 +355,11 @@ static int __devexit tps6507x_ts_remove(struct platform_device *pdev) > { > struct tps6507x_dev *tps6507x_dev = platform_get_drvdata(pdev); > struct tps6507x_ts *tsc = tps6507x_dev->ts; > - struct input_dev *input_dev = tsc->input_dev; > + struct input_dev *input_dev; > > if (!tsc) > return 0; > + input_dev = tsc->input_dev; > Why would tsc ever be NULL? Also I really do not like that pdev's driver data that is supposed to be driver-private data is being used by the parent. Parent should be using it's own drvdata and leave child's data alone. We should probably do in platform code what I2C is about to do and clear drvdata on unbind automatically to prevent this kind of misuse. -- Dmitry