tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/fpu head: 42088f5f7dcaf5e6d51b71cb32097ca4dad9b225 commit: 86d276af0556e9e6e579c71a48eff194d907be04 [6/9] jump_label, x86: Introduce jump_entry_size() config: x86_64-rhel-8.3 (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/fpu git checkout 86d276af0556e9e6e579c71a48eff194d907be04 # save the attached .config to linux build tree make W=1 ARCH=x86_64 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/x86/kernel/jump_label.c: In function '__jump_label_set_jump_code': 40 | if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) { | ^~~~~~~~~~~~~~~~~~~ | JUMP_LABEL_NOP arch/x86/kernel/jump_label.c:40:27: note: each undeclared identifier is reported only once for each function it appears in In file included from include/linux/kernel.h:16, from arch/x86/include/asm/percpu.h:27, from arch/x86/include/asm/current.h:6, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from include/linux/dev_printk.h:16, from include/linux/device.h:15, from include/linux/node.h:18, from include/linux/memory.h:19, from arch/x86/kernel/jump_label.c:9: arch/x86/kernel/jump_label.c:47:31: error: 'init' undeclared (first use in this function); did you mean 'int'? 47 | addr, addr, addr, expect, init, type); | ^~~~ include/linux/printk.h:333:34: note: in definition of macro 'pr_crit' 333 | printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__) | ^~~~~~~~~~~ arch/x86/kernel/jump_label.c: In function '__jump_label_transform': arch/x86/kernel/jump_label.c:76:5: error: 'JUMP_LABEL_NOP_SIZE' undeclared (first use in this function); did you mean 'JUMP_LABEL_NOP'? 76 | JUMP_LABEL_NOP_SIZE); | ^~~~~~~~~~~~~~~~~~~ | JUMP_LABEL_NOP arch/x86/kernel/jump_label.c: In function 'arch_jump_label_transform_queue': arch/x86/kernel/jump_label.c:114:12: error: 'JUMP_LABEL_NOP_SIZE' undeclared (first use in this function); did you mean 'JUMP_LABEL_NOP'? 114 | opcode, JUMP_LABEL_NOP_SIZE, NULL); | ^~~~~~~~~~~~~~~~~~~ | JUMP_LABEL_NOP vim +40 arch/x86/kernel/jump_label.c 86d276af0556e9e Peter Zijlstra 2019-06-28 23 18cbc8bed0c7079 Peter Zijlstra 2019-08-26 24 static const void * b9acd3e858cf960 Peter Zijlstra 2021-03-10 25 __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type) d9f5ab7b1c0a520 Jason Baron 2010-09-17 26 { 63f62addb88ec4b Peter Zijlstra 2019-10-03 27 const void *expect, *code; 63f62addb88ec4b Peter Zijlstra 2019-10-03 28 const void *addr, *dest; 9fc0f798ab8a6c0 Ard Biesheuvel 2018-09-18 29 63f62addb88ec4b Peter Zijlstra 2019-10-03 30 addr = (void *)jump_entry_code(entry); 63f62addb88ec4b Peter Zijlstra 2019-10-03 31 dest = (void *)jump_entry_target(entry); 18cbc8bed0c7079 Peter Zijlstra 2019-08-26 32 63f62addb88ec4b Peter Zijlstra 2019-10-03 33 code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); d9f5ab7b1c0a520 Jason Baron 2010-09-17 34 ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 35 if (type == JUMP_LABEL_JMP) ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 36 expect = x86_nops[5]; ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 37 else ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 38 expect = code; e71a5be15e47a73 Jeremy Fitzhardinge 2011-09-29 39 ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 @40 if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) { ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 41 /* ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 42 * The location is not an op that we were expecting. ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 43 * Something went wrong. Crash the box, as something could be ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 44 * corrupting the kernel. ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 45 */ ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 46 pr_crit("jump_label: Fatal kernel bug, unexpected op at %pS [%p] (%5ph != %5ph)) init:%d type:%d\n", ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 47 addr, addr, addr, expect, init, type); ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 48 BUG(); ea9a8a73e58ed8b Peter Zijlstra 2019-06-28 49 } 9fc0f798ab8a6c0 Ard Biesheuvel 2018-09-18 50 4cc6620b5e4c895 Daniel Bristot de Oliveira 2019-06-12 51 if (type == JUMP_LABEL_NOP) b9acd3e858cf960 Peter Zijlstra 2021-03-10 52 code = x86_nops[5]; 18cbc8bed0c7079 Peter Zijlstra 2019-08-26 53 63f62addb88ec4b Peter Zijlstra 2019-10-03 54 return code; 4cc6620b5e4c895 Daniel Bristot de Oliveira 2019-06-12 55 } 4cc6620b5e4c895 Daniel Bristot de Oliveira 2019-06-12 56 :::::: The code at line 40 was first introduced by commit :::::: ea9a8a73e58ed8b9a24d6c84c033c7064fe2a05c jump_label, x86: Improve error when we fail expected text :::::: TO: Peter Zijlstra <peterz(a)infradead.org&gt; :::::: CC: Peter Zijlstra <peterz(a)infradead.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org