On Tue 2022-03-01 10:24:48, Andrew Morton wrote: > On Tue, 1 Mar 2022 20:11:04 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > > > tree: https://github.com/hnaz/linux-mm master > > head: a46912c14343fd3269cc133494988af90b377d9f > > commit: b314f622e664eb263ea03ef7f4580e37146f123f [272/379] kallsyms: enhance %pS/s/b printing when KALLSYSMS is disabled > > config: arm-eseries_pxa_defconfig (https://download.01.org/0day-ci/archive/20220301/202203012040.uFWGm3My-lkp@xxxxxxxxx/config) > > compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0 > > reproduce (this is a W=1 build): > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > # https://github.com/hnaz/linux-mm/commit/b314f622e664eb263ea03ef7f4580e37146f123f > > git remote add hnaz-mm https://github.com/hnaz/linux-mm > > git fetch --no-tags hnaz-mm master > > git checkout b314f622e664eb263ea03ef7f4580e37146f123f > > # save the config file to linux build tree > > mkdir build_dir > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > All warnings (new ones prefixed by >>): > > > > lib/vsprintf.c: In function 'sprint_module_info': > > >> lib/vsprintf.c:991:13: warning: variable 'modbuildid' set but not used [-Wunused-but-set-variable] > > 991 | int modbuildid = 0; > > | ^~~~~~~~~~ > > Do we care about this? [-Wunused-but-set-variable isn't normally set. > Under what circumstances does it get set in your setup? > > I did this: > > --- a/lib/vsprintf.c~kallsyms-enhance-%ps-s-b-printing-when-kallsysms-is-disabled-fix > +++ a/lib/vsprintf.c > @@ -988,7 +988,7 @@ static int sprint_module_info(char *buf, > unsigned long base; > int ret = 0; > const char *modname; > - int modbuildid = 0; > + int modbuildid __maybe_unused = 0; > int len; > #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) > const unsigned char *buildid = NULL; Looks good. I would fix this. I am not sure but I guess that there are people that try to fix W=1 warnings. That said, I would prefer to disable the patch "kallsyms: enhance %pS/s/b printing when KALLSYSMS is disabled" for now. There are two problems with it: + It discloses the base address of loaded modules. I am not sure if it is acceptable from the security point of view. + It duplicates a lot of code from kallsyms.c. I would like to avoid it. I have pointed out both problems at https://lore.kernel.org/r/YhzywNowPiQm3IN4@alley I have to admit that they are hidden between less important comments. Best Regards, Petr
