Hi Gabriel, I love your patch! Yet something to improve: [auto build test ERROR on ext3/fsnotify] [also build test ERROR on linus/master v5.13-rc2 next-20210521] [cannot apply to ext4/dev] [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/Gabriel-Krisman-Bertazi/File-sys... base: https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git fsnotify config: um-allmodconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/a68dabe209f26c50d700b7be44603351f... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Gabriel-Krisman-Bertazi/File-system-wide-monitoring/20210522-235132 git checkout a68dabe209f26c50d700b7be44603351f95221cd # save the attached .config to linux build tree make W=1 ARCH=um If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): 23 | struct fanotify_event_info_header hdr; | ^~~ samples/fanotify/fs-monitor.c: In function 'handle_notifications': 55 | printf(" fsid: %llx\n", error->fsid); | ~~~^ ~~~~~~~~~~~ | | | | | __kernel_fsid_t {aka struct <anonymous>} | long long unsigned int samples/fanotify/fs-monitor.c: In function 'main': 76 | if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM, | ^~~~~~~~~~~~~~~~~~~ | FAN_MARK_FLUSH samples/fanotify/fs-monitor.c:76:37: note: each undeclared identifier is reported only once for each function it appears in vim +/hdr +23 samples/fanotify/fs-monitor.c 21 22 struct fanotify_event_info_error { 24 int error; 25 __kernel_fsid_t fsid; 26 unsigned long inode; 27 __u32 error_count; 28 }; 29 #endif 30 31 static void handle_notifications(char *buffer, int len) 32 { 33 struct fanotify_event_metadata *metadata; 34 struct fanotify_event_info_error *error; 35 36 for (metadata = (struct fanotify_event_metadata *) buffer; 37 FAN_EVENT_OK(metadata, len); metadata = FAN_EVENT_NEXT(metadata, len)) { 38 if (!(metadata->mask == FAN_ERROR)) { 39 printf("unexpected FAN MARK: %llx\n", metadata->mask); 40 continue; 41 } else if (metadata->fd != FAN_NOFD) { 42 printf("Unexpected fd (!= FAN_NOFD)\n"); 43 continue; 44 } 45 46 printf("FAN_ERROR found len=%d\n", metadata->event_len); 47 48 error = (struct fanotify_event_info_error *) (metadata+1); 49 if (error->hdr.info_type == FAN_EVENT_INFO_TYPE_ERROR) { 50 printf("unknown record: %d\n", error->hdr.info_type); 51 continue; 52 } 53 54 printf(" Generic Error Record: len=%d\n", error->hdr.len); 56 printf(" error: %d\n", error->error); 57 printf(" inode: %lu\n", error->inode); 58 printf(" error_count: %d\n", error->error_count); 59 } 60 } 61 62 int main(int argc, char **argv) 63 { 64 int fd; 65 char buffer[BUFSIZ]; 66 67 if (argc < 2) { 68 printf("Missing path argument\n"); 69 return 1; 70 } 71 72 fd = fanotify_init(FAN_CLASS_NOTIF, O_RDONLY); 73 if (fd < 0) 74 errx(1, "fanotify_init"); 75 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org