Hi Nick, I love your patch! Perhaps something to improve: [auto build test WARNING on kbuild/for-next] [also build test WARNING on v5.10-rc3 next-20201109] [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/Nick-Desaulniers/Revert-kbuild-Do-not-enable-Wimplicit-fallthrough-for-clang-for-now/20201109-093904 base: https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git for-next config: powerpc64-randconfig-r016-20201109 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 09ec07827b1128504457a93dee80b2ceee1af600) 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 # install powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://github.com/0day-ci/linux/commit/8b3537ff657d0124d47fbe215decbba65c4551ff git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nick-Desaulniers/Revert-kbuild-Do-not-enable-Wimplicit-fallthrough-for-clang-for-now/20201109-093904 git checkout 8b3537ff657d0124d47fbe215decbba65c4551ff # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from security/integrity/ima/ima_main.c:23: In file included from include/linux/mman.h:5: In file included from include/linux/mm.h:687: In file included from include/linux/huge_mm.h:8: In file included from include/linux/fs.h:33: In file included from include/linux/percpu-rwsem.h:7: In file included from include/linux/rcuwait.h:6: In file included from include/linux/sched/signal.h:6: include/linux/signal.h:241:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:241:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:241:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; include/linux/signal.h:253:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:253:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:253:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; >> security/integrity/ima/ima_main.c:746:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ security/integrity/ima/ima_main.c:746:2: note: insert 'break;' to avoid fall-through default: ^ break; 3 warnings generated. -- In file included from security/integrity/ima/ima_policy.c:13: In file included from include/linux/fs.h:33: In file included from include/linux/percpu-rwsem.h:7: In file included from include/linux/rcuwait.h:6: In file included from include/linux/sched/signal.h:6: include/linux/signal.h:241:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:241:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:241:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; include/linux/signal.h:253:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:253:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:253:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; >> security/integrity/ima/ima_policy.c:569:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ security/integrity/ima/ima_policy.c:569:3: note: insert 'break;' to avoid fall-through default: ^ break; security/integrity/ima/ima_policy.c:805:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ security/integrity/ima/ima_policy.c:805:2: note: insert 'break;' to avoid fall-through default: ^ break; 4 warnings generated. -- In file included from drivers/mmc/host/sdhci-of-arasan.c:22: In file included from include/linux/phy/phy.h:17: In file included from include/linux/regulator/consumer.h:35: In file included from include/linux/suspend.h:5: In file included from include/linux/swap.h:9: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:17: In file included from include/linux/fs.h:33: In file included from include/linux/percpu-rwsem.h:7: In file included from include/linux/rcuwait.h:6: In file included from include/linux/sched/signal.h:6: include/linux/signal.h:241:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:241:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:241:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; include/linux/signal.h:253:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 1: ; ^ include/linux/signal.h:253:2: note: insert '__attribute__((fallthrough));' to silence this warning case 1: ; ^ __attribute__((fallthrough)); include/linux/signal.h:253:2: note: insert 'break;' to avoid fall-through case 1: ; ^ break; >> drivers/mmc/host/sdhci-of-arasan.c:630:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ drivers/mmc/host/sdhci-of-arasan.c:630:2: note: insert 'break;' to avoid fall-through default: ^ break; drivers/mmc/host/sdhci-of-arasan.c:698:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ drivers/mmc/host/sdhci-of-arasan.c:698:2: note: insert 'break;' to avoid fall-through default: ^ break; drivers/mmc/host/sdhci-of-arasan.c:763:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ drivers/mmc/host/sdhci-of-arasan.c:763:2: note: insert 'break;' to avoid fall-through default: ^ break; drivers/mmc/host/sdhci-of-arasan.c:834:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] default: ^ drivers/mmc/host/sdhci-of-arasan.c:834:2: note: insert 'break;' to avoid fall-through default: ^ break; 6 warnings generated. -- >> lib/siphash.c:72:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ lib/siphash.c:72:2: note: insert '__attribute__((fallthrough));' to silence this warning case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ __attribute__((fallthrough)); lib/siphash.c:72:2: note: insert 'break;' to avoid fall-through case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ break; lib/siphash.c:73:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ lib/siphash.c:73:2: note: insert '__attribute__((fallthrough));' to silence this warning case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ __attribute__((fallthrough)); lib/siphash.c:73:2: note: insert 'break;' to avoid fall-through case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ break; lib/siphash.c:74:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 4: b |= le32_to_cpup(data); break; ^ lib/siphash.c:74:2: note: insert '__attribute__((fallthrough));' to silence this warning case 4: b |= le32_to_cpup(data); break; ^ __attribute__((fallthrough)); lib/siphash.c:74:2: note: insert 'break;' to avoid fall-through case 4: b |= le32_to_cpup(data); break; ^ break; lib/siphash.c:76:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 2: b |= le16_to_cpup(data); break; ^ lib/siphash.c:76:2: note: insert '__attribute__((fallthrough));' to silence this warning case 2: b |= le16_to_cpup(data); break; ^ __attribute__((fallthrough)); lib/siphash.c:76:2: note: insert 'break;' to avoid fall-through case 2: b |= le16_to_cpup(data); break; ^ break; lib/siphash.c:272:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ lib/siphash.c:272:2: note: insert '__attribute__((fallthrough));' to silence this warning case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ __attribute__((fallthrough)); lib/siphash.c:272:2: note: insert 'break;' to avoid fall-through case 6: b |= ((u64)end[5]) << 40; /* fall through */ ^ break; lib/siphash.c:273:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ lib/siphash.c:273:2: note: insert '__attribute__((fallthrough));' to silence this warning case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ __attribute__((fallthrough)); lib/siphash.c:273:2: note: insert 'break;' to avoid fall-through case 5: b |= ((u64)end[4]) << 32; /* fall through */ ^ break; lib/siphash.c:274:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 4: b |= le32_to_cpup(data); break; ^ lib/siphash.c:274:2: note: insert '__attribute__((fallthrough));' to silence this warning case 4: b |= le32_to_cpup(data); break; ^ __attribute__((fallthrough)); lib/siphash.c:274:2: note: insert 'break;' to avoid fall-through case 4: b |= le32_to_cpup(data); break; ^ break; lib/siphash.c:276:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] case 2: b |= le16_to_cpup(data); break; ^ lib/siphash.c:276:2: note: insert '__attribute__((fallthrough));' to silence this warning case 2: b |= le16_to_cpup(data); break; ^ __attribute__((fallthrough)); lib/siphash.c:276:2: note: insert 'break;' to avoid fall-through case 2: b |= le16_to_cpup(data); break; ^ break; 8 warnings generated. vim +746 security/integrity/ima/ima_main.c 5a9196d715607f7 Mimi Zohar 2014-07-22 699 16c267aac86b463 Mimi Zohar 2018-07-13 700 /** 16c267aac86b463 Mimi Zohar 2018-07-13 701 * ima_load_data - appraise decision based on policy 16c267aac86b463 Mimi Zohar 2018-07-13 702 * @id: kernel load data caller identifier b64fcae74b6d694 Kees Cook 2020-10-02 703 * @contents: whether the full contents will be available in a later b64fcae74b6d694 Kees Cook 2020-10-02 704 * call to ima_post_load_data(). 16c267aac86b463 Mimi Zohar 2018-07-13 705 * 16c267aac86b463 Mimi Zohar 2018-07-13 706 * Callers of this LSM hook can not measure, appraise, or audit the 16c267aac86b463 Mimi Zohar 2018-07-13 707 * data provided by userspace. Enforce policy rules requring a file 16c267aac86b463 Mimi Zohar 2018-07-13 708 * signature (eg. kexec'ed kernel image). 16c267aac86b463 Mimi Zohar 2018-07-13 709 * 16c267aac86b463 Mimi Zohar 2018-07-13 710 * For permission return 0, otherwise return -EACCES. 16c267aac86b463 Mimi Zohar 2018-07-13 711 */ b64fcae74b6d694 Kees Cook 2020-10-02 712 int ima_load_data(enum kernel_load_data_id id, bool contents) 16c267aac86b463 Mimi Zohar 2018-07-13 713 { b5ca117365d960f Nayna Jain 2018-10-09 714 bool ima_enforce, sig_enforce; c77b8cdf745d91e Mimi Zohar 2018-07-13 715 b5ca117365d960f Nayna Jain 2018-10-09 716 ima_enforce = b5ca117365d960f Nayna Jain 2018-10-09 717 (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE; 16c267aac86b463 Mimi Zohar 2018-07-13 718 16c267aac86b463 Mimi Zohar 2018-07-13 719 switch (id) { 16c267aac86b463 Mimi Zohar 2018-07-13 720 case LOADING_KEXEC_IMAGE: 99d5cadfde2b1ac Jiri Bohac 2019-08-19 721 if (IS_ENABLED(CONFIG_KEXEC_SIG) b5ca117365d960f Nayna Jain 2018-10-09 722 && arch_ima_get_secureboot()) { b5ca117365d960f Nayna Jain 2018-10-09 723 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); b5ca117365d960f Nayna Jain 2018-10-09 724 return -EACCES; b5ca117365d960f Nayna Jain 2018-10-09 725 } b5ca117365d960f Nayna Jain 2018-10-09 726 b5ca117365d960f Nayna Jain 2018-10-09 727 if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) { 16c267aac86b463 Mimi Zohar 2018-07-13 728 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); 16c267aac86b463 Mimi Zohar 2018-07-13 729 return -EACCES; /* INTEGRITY_UNKNOWN */ 16c267aac86b463 Mimi Zohar 2018-07-13 730 } fed2512a7ccc8fc Mimi Zohar 2018-07-13 731 break; fed2512a7ccc8fc Mimi Zohar 2018-07-13 732 case LOADING_FIRMWARE: 4f2d99b06b73800 Kees Cook 2020-10-02 733 if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) { fed2512a7ccc8fc Mimi Zohar 2018-07-13 734 pr_err("Prevent firmware sysfs fallback loading.\n"); fed2512a7ccc8fc Mimi Zohar 2018-07-13 735 return -EACCES; /* INTEGRITY_UNKNOWN */ fed2512a7ccc8fc Mimi Zohar 2018-07-13 736 } c77b8cdf745d91e Mimi Zohar 2018-07-13 737 break; c77b8cdf745d91e Mimi Zohar 2018-07-13 738 case LOADING_MODULE: c77b8cdf745d91e Mimi Zohar 2018-07-13 739 sig_enforce = is_module_sig_enforced(); c77b8cdf745d91e Mimi Zohar 2018-07-13 740 b5ca117365d960f Nayna Jain 2018-10-09 741 if (ima_enforce && (!sig_enforce b5ca117365d960f Nayna Jain 2018-10-09 742 && (ima_appraise & IMA_APPRAISE_MODULES))) { c77b8cdf745d91e Mimi Zohar 2018-07-13 743 pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); c77b8cdf745d91e Mimi Zohar 2018-07-13 744 return -EACCES; /* INTEGRITY_UNKNOWN */ c77b8cdf745d91e Mimi Zohar 2018-07-13 745 } 16c267aac86b463 Mimi Zohar 2018-07-13 @746 default: 16c267aac86b463 Mimi Zohar 2018-07-13 747 break; 16c267aac86b463 Mimi Zohar 2018-07-13 748 } 16c267aac86b463 Mimi Zohar 2018-07-13 749 return 0; 16c267aac86b463 Mimi Zohar 2018-07-13 750 } 16c267aac86b463 Mimi Zohar 2018-07-13 751 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org