Hi Kees, I love your patch! Yet something to improve: [auto build test ERROR on hnaz-mm/master] [also build test ERROR on kees/for-next/pstore v5.17-rc4 next-20220216] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Kees-Cook/usercopy-Check-valid-lifetime-via-stack-depth/20220217-041611 base: https://github.com/hnaz/linux-mm master config: openrisc-randconfig-r002-20220216 (https://download.01.org/0day-ci/archive/20220217/202202170844.jnpFFEmh-lkp@intel.com/config) compiler: or1k-linux-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/0day-ci/linux/commit/77944e5fa0cf5a29903b72466a22152c6a5d41ac git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Kees-Cook/usercopy-Check-valid-lifetime-via-stack-depth/20220217-041611 git checkout 77944e5fa0cf5a29903b72466a22152c6a5d41ac # 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=openrisc SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): mm/usercopy.c: In function 'check_stack_object': >> mm/usercopy.c:41:42: error: 'current_stack_pointer' undeclared (first use in this function); did you mean 'user_stack_pointer'? 41 | const void * const low = (void *)current_stack_pointer; | ^~~~~~~~~~~~~~~~~~~~~ | user_stack_pointer mm/usercopy.c:41:42: note: each undeclared identifier is reported only once for each function it appears in mm/usercopy.c: In function '__check_object_size': mm/usercopy.c:287:41: error: 'current_stack_pointer' undeclared (first use in this function); did you mean 'user_stack_pointer'? 287 | (void *)current_stack_pointer - ptr, | ^~~~~~~~~~~~~~~~~~~~~ | user_stack_pointer vim +41 mm/usercopy.c 24 25 /* 26 * Checks if a given pointer and length is contained by the current 27 * stack frame (if possible). 28 * 29 * Returns: 30 * NOT_STACK: not at all on the stack 31 * GOOD_FRAME: fully within a valid stack frame 32 * GOOD_STACK: within the current stack (when can't frame-check exactly) 33 * BAD_STACK: error condition (invalid stack position or bad stack frame) 34 */ 35 static noinline int check_stack_object(const void *obj, unsigned long len) 36 { 37 const void * const stack = task_stack_page(current); 38 const void * const stackend = stack + THREAD_SIZE; 39 #ifndef CONFIG_STACK_GROWSUP 40 const void * const high = stackend; > 41 const void * const low = (void *)current_stack_pointer; 42 #else 43 const void * const high = (void *)current_stack_pointer; 44 const void * const low = stack; 45 #endif 46 int ret; 47 48 /* Object is not on the stack at all. */ 49 if (obj + len <= stack || stackend <= obj) 50 return NOT_STACK; 51 52 /* 53 * Reject: object partially overlaps the stack (passing the 54 * check above means at least one end is within the stack, 55 * so if this check fails, the other end is outside the stack). 56 */ 57 if (obj < stack || stackend < obj + len) 58 return BAD_STACK; 59 60 /* Check if object is safely within a valid frame. */ 61 ret = arch_within_stack_frames(stack, stackend, obj, len); 62 if (ret) 63 return ret; 64 65 /* 66 * Reject: object not within current stack depth. 67 */ 68 if (obj < low || high < obj + len) 69 return BAD_STACK; 70 71 return GOOD_STACK; 72 } 73 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org