On Fri, 28 Aug 2020, Denis Efremov wrote: > Hi all, > > On 8/27/20 10:42 PM, Julia Lawall wrote: > > > > > > On Thu, 27 Aug 2020, Joe Perches wrote: > > > >> On Thu, 2020-08-27 at 15:48 +0100, Alex Dewar wrote: > >>> On Thu, Aug 27, 2020 at 03:41:06PM +0200, Rasmus Villemoes wrote: > >>>> On 27/08/2020 15.18, Alex Dewar wrote: > >>>>> On Thu, Aug 27, 2020 at 09:15:37AM +0200, Greg Kroah-Hartman wrote: > >>>>>> On Thu, Aug 27, 2020 at 08:42:06AM +0200, Rasmus Villemoes wrote: > >>>>>>> On 25/08/2020 00.23, Alex Dewar wrote: > >>>>>>>> kernel/cpu.c: don't use snprintf() for sysfs attrs > >>>>>>>> > >>>>>>>> As per the documentation (Documentation/filesystems/sysfs.rst), > >>>>>>>> snprintf() should not be used for formatting values returned by sysfs. > > Just FYI, I've send an addition to the device_attr_show.cocci script[1] to turn > simple cases of snprintf (e.g. "%i") to sprintf. Looks like many developers would > like it more than changing snprintf to scnprintf. As for me, I don't like the idea > of automated altering of the original logic from bounded snprint to unbouded one > with sprintf. > > [1] https://lkml.org/lkml/2020/8/13/786 > > Regarding current device_attr_show.cocci implementation, it detects the functions > by declaration: > ssize_t any_name(struct device *dev, struct device_attribute *attr, char *buf) > > and I limited the check to: > "return snprintf" > pattern because there are already too many warnings. > > Actually, it looks more correct to check for: > ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) > { > <... > * snprintf@p(...); > ...> > } > > This pattern should also highlight the snprintf calls there we save returned > value in a var, e.g.: > > ret += snprintf(...); > ... > ret += snprintf(...); > ... > ret += snprintf(...); > > return ret; > > > > > Something like > > > > identifier f; > > fresh identifier = "sysfs" ## f; > > > > may be useful. Let me know if further help is needed. > > Initially, I wrote the rule to search for DEVICE_ATTR(..., ..., func_name, ...) This is what I would have expected. > functions. However, it looks like matching function prototype is enough. At least, > I failed to find false positives. I rejected the initial DEVICE_ATTR() searching > because I thought that it's impossible to handle DEVICE_ATTR_RO()/DEVICE_ATTR_RW() > macroses with coccinelle as they "generate" function names internally with > "##". "fresh identifier" should really help here, but now I doubt it's required in > device_attr_show.cocci, function prototype is enough. It's true that it is probably unique enough. julia
