tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/core head: 1c05e501b4d6147fd45c438f0d80067dc946cd15 commit: 1c05e501b4d6147fd45c438f0d80067dc946cd15 [3/3] x86/kprobes: Use int3 instead of debug trap for single-step config: i386-randconfig-r021-20210323 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?... git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git git fetch --no-tags peterz-queue x86/core git checkout 1c05e501b4d6147fd45c438f0d80067dc946cd15 # save the attached .config to linux build tree make W=1 ARCH=i386 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 >>): 940 | static int nokprobe_inline kprobe_is_ss(struct kprobe_ctlblk *kcb) | ^~~~~~ arch/x86/kernel/kprobes/core.c:1060:24: warning: no previous prototype for 'trampoline_handler' [-Wmissing-prototypes] 1060 | __used __visible void *trampoline_handler(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~ vim +/inline +940 arch/x86/kernel/kprobes/core.c 939 941 { 942 return (kcb->kprobe_status == KPROBE_HIT_SS || 943 kcb->kprobe_status == KPROBE_REENTER); 944 } 945 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org