From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Date: Thu, 27 May 2010 16:21:42 +0000 Subject: Re: [PATCH 9/11] drivers/platform/x86: Eliminate a NULL pointer dereference Message-Id: <201005270921.43049.dmitry.torokhov@gmail.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Julia Lawall Cc: Mattia Dongili , Matthew Garrett , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org On Thursday 27 May 2010 05:37:00 am Julia Lawall wrote: > From: Julia Lawall > > Give different error messages if device_enum is NULL or if its type field > has the wrong value. > > A simplified version of the semantic match that finds this problem is as > follows: (http://coccinelle.lip6.fr/) > > // > @r exists@ > expression E,E1; > identifier f; > statement S1,S2,S3; > @@ > > if ((E = NULL && ...) || ...) > { > ... when != if (...) S1 else S2 > when != E = E1 > * E->f > ... when any > return ...; > } > else S3 > // > > Signed-off-by: Julia Lawall > > --- > This may be too much clutter for little benefit. Other, perhaps less > informative solutions are possible. Verbosity should be OK but I think that mixing pr_xxx() and naked printks in the same patch is not very nice. > > drivers/platform/x86/sony-laptop.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/platform/x86/sony-laptop.c > b/drivers/platform/x86/sony-laptop.c index 1387c5f..9db8d2b 100644 > --- a/drivers/platform/x86/sony-laptop.c > +++ b/drivers/platform/x86/sony-laptop.c > @@ -1196,8 +1196,12 @@ static void sony_nc_rfkill_setup(struct acpi_device > *device) } > > device_enum = (union acpi_object *) buffer.pointer; > - if (!device_enum || device_enum->type != ACPI_TYPE_BUFFER) { > - printk(KERN_ERR "Invalid SN06 return object 0x%.2x\n", > + if (!device_enum) { > + pr_err("Invalid SN06 return object\n"); > + goto out_no_enum; > + } > + if (device_enum->type != ACPI_TYPE_BUFFER) { > + printk(KERN_ERR "Invalid SN06 return object type 0x%.2x\n", > device_enum->type); > goto out_no_enum; > } Thanks. -- Dmitry From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH 9/11] drivers/platform/x86: Eliminate a NULL pointer dereference Date: Thu, 27 May 2010 09:21:42 -0700 Message-ID: <201005270921.43049.dmitry.torokhov@gmail.com> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Julia Lawall Cc: Mattia Dongili , Matthew Garrett , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org List-Id: platform-driver-x86.vger.kernel.org On Thursday 27 May 2010 05:37:00 am Julia Lawall wrote: > From: Julia Lawall > > Give different error messages if device_enum is NULL or if its type field > has the wrong value. > > A simplified version of the semantic match that finds this problem is as > follows: (http://coccinelle.lip6.fr/) > > // > @r exists@ > expression E,E1; > identifier f; > statement S1,S2,S3; > @@ > > if ((E == NULL && ...) || ...) > { > ... when != if (...) S1 else S2 > when != E = E1 > * E->f > ... when any > return ...; > } > else S3 > // > > Signed-off-by: Julia Lawall > > --- > This may be too much clutter for little benefit. Other, perhaps less > informative solutions are possible. Verbosity should be OK but I think that mixing pr_xxx() and naked printks in the same patch is not very nice. > > drivers/platform/x86/sony-laptop.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/platform/x86/sony-laptop.c > b/drivers/platform/x86/sony-laptop.c index 1387c5f..9db8d2b 100644 > --- a/drivers/platform/x86/sony-laptop.c > +++ b/drivers/platform/x86/sony-laptop.c > @@ -1196,8 +1196,12 @@ static void sony_nc_rfkill_setup(struct acpi_device > *device) } > > device_enum = (union acpi_object *) buffer.pointer; > - if (!device_enum || device_enum->type != ACPI_TYPE_BUFFER) { > - printk(KERN_ERR "Invalid SN06 return object 0x%.2x\n", > + if (!device_enum) { > + pr_err("Invalid SN06 return object\n"); > + goto out_no_enum; > + } > + if (device_enum->type != ACPI_TYPE_BUFFER) { > + printk(KERN_ERR "Invalid SN06 return object type 0x%.2x\n", > device_enum->type); > goto out_no_enum; > } Thanks. -- Dmitry