| Message ID | 20170714120720.906842-15-arnd@arndb.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | gcc-7 -Wformat-* warnings | expand |
On 14/07/17 14:07, Arnd Bergmann wrote: > gcc-7 notices that we copy a fixed length string into another > string of the same size, with additional characters: > > drivers/media/usb/usbvision/usbvision-i2c.c: In function 'usbvision_i2c_register': > drivers/media/usb/usbvision/usbvision-i2c.c:190:36: error: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 47 [-Werror=format-overflow=] > sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, > ^~~~~~~~~~ > drivers/media/usb/usbvision/usbvision-i2c.c:190:2: note: 'sprintf' output between 4 and 76 bytes into a destination of size 48 > > We know this is fine as the template name is always "usbvision", so > we can easily avoid the warning by using this as the format string > directly. Hmm, how about replacing sprintf by snprintf? That feels a lot safer (this is very old code, it's not surprising it is still using sprintf). Regards, Hans > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/media/usb/usbvision/usbvision-i2c.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/usb/usbvision/usbvision-i2c.c b/drivers/media/usb/usbvision/usbvision-i2c.c > index fdf6b6e285da..aae9f69884da 100644 > --- a/drivers/media/usb/usbvision/usbvision-i2c.c > +++ b/drivers/media/usb/usbvision/usbvision-i2c.c > @@ -187,8 +187,8 @@ int usbvision_i2c_register(struct usb_usbvision *usbvision) > > usbvision->i2c_adap = i2c_adap_template; > > - sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, > - usbvision->dev->bus->busnum, usbvision->dev->devpath); > + sprintf(usbvision->i2c_adap.name, "usbvision-%d-%s", > + usbvision->dev->bus->busnum, usbvision->dev->devpath); > PDEBUG(DBG_I2C, "Adaptername: %s", usbvision->i2c_adap.name); > usbvision->i2c_adap.dev.parent = &usbvision->dev->dev; > >
On Mon, Jul 17, 2017 at 2:53 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote: > On 14/07/17 14:07, Arnd Bergmann wrote: >> gcc-7 notices that we copy a fixed length string into another >> string of the same size, with additional characters: >> >> drivers/media/usb/usbvision/usbvision-i2c.c: In function 'usbvision_i2c_register': >> drivers/media/usb/usbvision/usbvision-i2c.c:190:36: error: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 47 [-Werror=format-overflow=] >> sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, >> ^~~~~~~~~~ >> drivers/media/usb/usbvision/usbvision-i2c.c:190:2: note: 'sprintf' output between 4 and 76 bytes into a destination of size 48 >> >> We know this is fine as the template name is always "usbvision", so >> we can easily avoid the warning by using this as the format string >> directly. > > Hmm, how about replacing sprintf by snprintf? That feels a lot safer (this is very > old code, it's not surprising it is still using sprintf). With snprintf(), you will still get a -Wformat-truncation warning. One of my patches disables that warning by default, but Mauro likes build-testing with "make W=1", so it would still show up then. However, we can do both: replace the string and use snprintf(). Arnd
On 17/07/17 14:57, Arnd Bergmann wrote: > On Mon, Jul 17, 2017 at 2:53 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote: >> On 14/07/17 14:07, Arnd Bergmann wrote: >>> gcc-7 notices that we copy a fixed length string into another >>> string of the same size, with additional characters: >>> >>> drivers/media/usb/usbvision/usbvision-i2c.c: In function 'usbvision_i2c_register': >>> drivers/media/usb/usbvision/usbvision-i2c.c:190:36: error: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 47 [-Werror=format-overflow=] >>> sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, >>> ^~~~~~~~~~ >>> drivers/media/usb/usbvision/usbvision-i2c.c:190:2: note: 'sprintf' output between 4 and 76 bytes into a destination of size 48 >>> >>> We know this is fine as the template name is always "usbvision", so >>> we can easily avoid the warning by using this as the format string >>> directly. >> >> Hmm, how about replacing sprintf by snprintf? That feels a lot safer (this is very >> old code, it's not surprising it is still using sprintf). > > With snprintf(), you will still get a -Wformat-truncation warning. One > of my patches > disables that warning by default, but Mauro likes build-testing with > "make W=1", so > it would still show up then. > > However, we can do both: replace the string and use snprintf(). Yes please! Regards, Hans
diff --git a/drivers/media/usb/usbvision/usbvision-i2c.c b/drivers/media/usb/usbvision/usbvision-i2c.c index fdf6b6e285da..aae9f69884da 100644 --- a/drivers/media/usb/usbvision/usbvision-i2c.c +++ b/drivers/media/usb/usbvision/usbvision-i2c.c @@ -187,8 +187,8 @@ int usbvision_i2c_register(struct usb_usbvision *usbvision) usbvision->i2c_adap = i2c_adap_template; - sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, - usbvision->dev->bus->busnum, usbvision->dev->devpath); + sprintf(usbvision->i2c_adap.name, "usbvision-%d-%s", + usbvision->dev->bus->busnum, usbvision->dev->devpath); PDEBUG(DBG_I2C, "Adaptername: %s", usbvision->i2c_adap.name); usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;
gcc-7 notices that we copy a fixed length string into another string of the same size, with additional characters: drivers/media/usb/usbvision/usbvision-i2c.c: In function 'usbvision_i2c_register': drivers/media/usb/usbvision/usbvision-i2c.c:190:36: error: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 47 [-Werror=format-overflow=] sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, ^~~~~~~~~~ drivers/media/usb/usbvision/usbvision-i2c.c:190:2: note: 'sprintf' output between 4 and 76 bytes into a destination of size 48 We know this is fine as the template name is always "usbvision", so we can easily avoid the warning by using this as the format string directly. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/media/usb/usbvision/usbvision-i2c.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.9.0