Hi Arnd, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 368094df48e680fa51cedb68537408cfa64b788e commit: 17132da70eb766785b9b4677bacce18cc11ea442 ARM: samsung: move pm check code to drivers/soc date: 10 months ago config: arm-randconfig-r031-20210609 (attached as .config) compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0 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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 17132da70eb766785b9b4677bacce18cc11ea442 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/soc/samsung/s3c-pm-debug.c: In function 's3c_pm_dbg': 30 | vsnprintf(buff, sizeof(buff), fmt, va); | ^~~~~~~~~ vim +30 drivers/soc/samsung/s3c-pm-debug.c 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 23 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 24 void s3c_pm_dbg(const char *fmt, ...) 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 25 { 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 26 va_list va; 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 27 char buff[256]; 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 28 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 29 va_start(va, fmt); 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 @30 vsnprintf(buff, sizeof(buff), fmt, va); 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 31 va_end(va); 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 32 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 33 printascii(buff); 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 34 } 72551f6cf13e2f arch/arm/plat-samsung/pm-debug.c Tomasz Figa 2014-03-18 35 :::::: The code at line 30 was first introduced by commit :::::: 72551f6cf13e2f3a1d273b7007b5d7d7fd69c554 ARM: SAMSUNG: Move Samsung PM debug code into separate file :::::: TO: Tomasz Figa <t.figa(a)samsung.com&gt; :::::: CC: Kukjin Kim <kgene.kim(a)samsung.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org