Hi Huang, Thank you for the patch! Yet something to improve: [auto build test ERROR on tip/perf/core] [also build test ERROR on trace/for-next linus/master v5.12-rc2 next-20210312] [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/Huang-Pei/MIPS-replace-pg-with-C... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 8bcfdd7cad3dffdd340f9a79098cbf331eb2cd53 config: mips-allyesconfig (attached as .config) compiler: mips-linux-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://github.com/0day-ci/linux/commit/c81a1cbcfd0d4b65f668fd824466b9bce... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Huang-Pei/MIPS-replace-pg-with-CC_FLAGS_FTRACE/20210313-154234 git checkout c81a1cbcfd0d4b65f668fd824466b9bce02cee74 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 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 >>): 170 | void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, | ^~~~~~~~~~~~~~~~~~~~~ In file included from arch/mips/kernel/ftrace.c:10: include/linux/kprobes.h:362:13: note: previous declaration of 'kprobe_ftrace_handler' was here 362 | extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, | ^~~~~~~~~~~~~~~~~~~~~ arch/mips/kernel/ftrace.c:226:15: warning: no previous prototype for 'prepare_ftrace_return' [-Wmissing-prototypes] 226 | unsigned long prepare_ftrace_return(unsigned long parent, unsigned long self_ra, | ^~~~~~~~~~~~~~~~~~~~~ vim +/kprobe_ftrace_handler +170 arch/mips/kernel/ftrace.c 169 171 struct ftrace_ops *ops, struct pt_regs *regs) 172 { 173 struct kprobe *p; 174 struct kprobe_ctlblk *kcb; 175 unsigned long orig_ip; 176 177 p = get_kprobe((kprobe_opcode_t *)ip); 178 if (unlikely(!p) || kprobe_disabled(p)) 179 return; 180 181 kcb = get_kprobe_ctlblk(); 182 if (kprobe_running()) { 183 kprobes_inc_nmissed_count(p); 184 } else { 185 /* 186 * pre_handler need epc point to the kprobe 187 * 188 */ 189 orig_ip = instruction_pointer(regs); 190 instruction_pointer_set(regs, (unsigned long)p->addr); 191 __this_cpu_write(current_kprobe, p); 192 kcb->kprobe_status = KPROBE_HIT_ACTIVE; 193 if (!p->pre_handler || !p->pre_handler(p, regs)) { 194 /* 195 * Emulate singlestep (and also recover regs->nip) 196 * as if there is a nop 197 */ 198 if (unlikely(p->post_handler)) { 199 kcb->kprobe_status = KPROBE_HIT_SSDONE; 200 if ((unsigned long)p->addr == (ip + 4)) 201 202 ip = (unsigned long)p->addr + 8; 203 else 204 ip = (unsigned long)p->addr + 4; 205 instruction_pointer_set(regs, ip); 206 p->post_handler(p, regs, 0); 207 } 208 } 209 instruction_pointer_set(regs, orig_ip); 210 /* 211 * If pre_handler returns !0, we have to 212 * skip emulating post_handler. 213 */ 214 __this_cpu_write(current_kprobe, NULL); 215 } 216 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org