Hi Michael, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y head: 7281e11121f6fb47ea1e757b7781c5c15e3781fe commit: 57ac40ee09cea2ec90f71c6f49b15d0d82667b38 [2397/3689] powerpc: Drop -me200 addition to build flags config: powerpc64-randconfig-p001-20210318 (attached as .config) compiler: powerpc-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://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-4.19.y git checkout 57ac40ee09cea2ec90f71c6f49b15d0d82667b38 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc64 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 >>): 1285 | void show_user_instructions(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors -- arch/powerpc/kernel/traps.c:1880:6: error: no previous prototype for 'DebugException' [-Werror=missing-prototypes] 1880 | void DebugException(struct pt_regs *regs, unsigned long debug_status) | ^~~~~~~~~~~~~~ 1993 | void CacheLockingException(struct pt_regs *regs, unsigned long address, | ^~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors -- arch/powerpc/mm/fsl_booke_mmu.c:70:15: error: no previous prototype for 'tlbcam_sz' [-Werror=missing-prototypes] 70 | unsigned long tlbcam_sz(int idx) | ^~~~~~~~~ 269 | notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) | ^~~~~~~~~~~~~ cc1: all warnings being treated as errors -- arch/powerpc/perf/core-fsl-emb.c: In function 'perf_event_interrupt': 665 | int found = 0; | ^~~~~ arch/powerpc/perf/core-fsl-emb.c: At top level: 704 | void hw_perf_event_setup(int cpu) | ^~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for HOTPLUG_CPU Depends on SMP && (PPC_PSERIES || PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE Selected by - PM_SLEEP_SMP && SMP && (ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE && PM_SLEEP WARNING: unmet direct dependencies detected for FSL_EMB_PERFMON Depends on E500 || PPC_83xx Selected by - PPC_FSL_BOOK3E vim +/show_user_instructions +1285 arch/powerpc/kernel/process.c 06d67d54741a5b Paul Mackerras 2005-10-10 1284 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 @1285 void show_user_instructions(struct pt_regs *regs) 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1286 { 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1287 unsigned long pc; 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1288 int i; 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1289 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1290 pc = regs->nip - (instructions_to_print * 3 / 4 * sizeof(int)); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1291 a932ed3b718147 Michael Ellerman 2018-10-05 1292 /* a932ed3b718147 Michael Ellerman 2018-10-05 1293 * Make sure the NIP points at userspace, not kernel text/data or a932ed3b718147 Michael Ellerman 2018-10-05 1294 * elsewhere. a932ed3b718147 Michael Ellerman 2018-10-05 1295 */ a932ed3b718147 Michael Ellerman 2018-10-05 1296 if (!__access_ok(pc, instructions_to_print * sizeof(int), USER_DS)) { a932ed3b718147 Michael Ellerman 2018-10-05 1297 pr_info("%s[%d]: Bad NIP, not dumping instructions.\n", a932ed3b718147 Michael Ellerman 2018-10-05 1298 current->comm, current->pid); a932ed3b718147 Michael Ellerman 2018-10-05 1299 return; a932ed3b718147 Michael Ellerman 2018-10-05 1300 } a932ed3b718147 Michael Ellerman 2018-10-05 1301 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1302 pr_info("%s[%d]: code: ", current->comm, current->pid); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1303 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1304 for (i = 0; i < instructions_to_print; i++) { 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1305 int instr; 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1306 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1307 if (!(i % 8) && (i > 0)) { 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1308 pr_cont("\n"); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1309 pr_info("%s[%d]: code: ", current->comm, current->pid); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1310 } 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1311 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1312 if (probe_kernel_address((unsigned int __user *)pc, instr)) { 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1313 pr_cont("XXXXXXXX "); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1314 } else { 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1315 if (regs->nip == pc) 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1316 pr_cont("<%08x> ", instr); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1317 else 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1318 pr_cont("%08x ", instr); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1319 } 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1320 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1321 pc += sizeof(int); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1322 } 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1323 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1324 pr_cont("\n"); 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1325 } 88b0fe17573592 Murilo Opsfelder Araujo 2018-08-01 1326 :::::: The code at line 1285 was first introduced by commit :::::: 88b0fe17573592a8e3196bf143f865da460178e7 powerpc: Add show_user_instructions() :::::: TO: Murilo Opsfelder Araujo <muriloo(a)linux.ibm.com&gt; :::::: CC: Michael Ellerman <mpe(a)ellerman.id.au&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org