tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.4.y head: 95a3867e897abd7811196123f81a119a75aba863 commit: 7a5c21af789d6871de3f05185e221fb7eea6804b [7532/9999] MIPS: fw: sni: Fix out of bounds init of o32 stack config: mips-randconfig-r016-20210209 (attached as .config) compiler: mips64-linux-gcc (GCC) 7.5.0 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/stable/linux-stable-rc.gi... git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git git fetch --no-tags linux-stable-rc linux-4.4.y git checkout 7a5c21af789d6871de3f05185e221fb7eea6804b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): arch/mips/fw/sni/sniprom.c:67:6: warning: no previous prototype for 'prom_putchar' [-Wmissing-prototypes] void prom_putchar(char c) ^~~~~~~~~~~~ In file included from include/linux/compiler.h:72:0, from include/linux/linkage.h:4, from include/linux/kernel.h:6, from arch/mips/fw/sni/sniprom.c:12: arch/mips/fw/sni/sniprom.c: In function 'prom_putchar': #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) ^ include/linux/kernel.h:54:59: note: in expansion of macro '__must_be_array' #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) ^~~~~~~~~~~~~~~ arch/mips/fw/sni/sniprom.c:45:29: note: in expansion of macro 'ARRAY_SIZE' #define O32_STK (&o32_stk[ARRAY_SIZE(o32_stk)]) ^~~~~~~~~~ arch/mips/fw/sni/sniprom.c:55:62: note: in expansion of macro 'O32_STK' #define _prom_putchar(x) __prom_putchar(___prom_putchar, O32_STK, x) ^~~~~~~ arch/mips/fw/sni/sniprom.c:69:2: note: in expansion of macro '_prom_putchar' _prom_putchar(c); ^~~~~~~~~~~~~ arch/mips/fw/sni/sniprom.c: At top level: arch/mips/fw/sni/sniprom.c:78:7: warning: no previous prototype for 'prom_get_hwconf' [-Wmissing-prototypes] void *prom_get_hwconf(void) ^~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/BUILD_BUG_ON_ZERO +64 include/linux/compiler-gcc.h a1365647022eb0 Andrew Morton 2006-01-08 55 fe8c8a126806fe Cesar Eduardo Barros 2013-11-25 56 /* Make the optimizer believe the variable can be manipulated arbitrarily. */ f6d133f877c8bb Joe Perches 2015-06-25 57 #define OPTIMIZER_HIDE_VAR(var) \ f6d133f877c8bb Joe Perches 2015-06-25 58 __asm__ ("" : "=r" (var) : "0" (var)) fe8c8a126806fe Cesar Eduardo Barros 2013-11-25 59 5bd7e6a30e1eb3 KOSAKI Motohiro 2011-05-24 60 #ifdef __CHECKER__ f6d133f877c8bb Joe Perches 2015-06-25 61 #define __must_be_array(a) 0 5bd7e6a30e1eb3 KOSAKI Motohiro 2011-05-24 62 #else c5e631cf65f4d6 Rusty Russell 2007-05-06 63 /* &a[0] degrades to a pointer: a different type from an array */ ea6b101d8a3ea4 Rusty Russell 2010-08-09 @64 #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) 5bd7e6a30e1eb3 KOSAKI Motohiro 2011-05-24 65 #endif a1365647022eb0 Andrew Morton 2006-01-08 66 :::::: The code at line 64 was first introduced by commit :::::: ea6b101d8a3ea4e1dec29df31188c2f9852296fe include/linux/compiler-gcc.h: use __same_type() in __must_be_array() :::::: TO: Rusty Russell <rusty(a)rustcorp.com.au&gt; :::::: CC: Linus Torvalds <torvalds(a)linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org