Hi WoZ1zh1, kernel test robot noticed the following build warnings: [auto build test WARNING on next-20231108] url: https://github.com/intel-lab-lkp/linux/commits/WoZ1zh1/proc-support-file-f_pos-checking-in-mem_lseek/20231109-103353 base: next-20231108 patch link: https://lore.kernel.org/r/20231109102658.2075547-1-wozizhi%40huawei.com patch subject: [PATCH -next V2] proc: support file->f_pos checking in mem_lseek config: arc-randconfig-001-20231109 (https://download.01.org/0day-ci/archive/20231109/202311091307.k2L6reDL-lkp@xxxxxxxxx/config) compiler: arc-elf-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231109/202311091307.k2L6reDL-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202311091307.k2L6reDL-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): fs/proc/base.c: In function 'mem_lseek': >> fs/proc/base.c:911:24: warning: this statement may fall through [-Wimplicit-fallthrough=] 911 | offset += file->f_pos; | ~~~~~~~^~~~~~~~~~~~~~ fs/proc/base.c:912:9: note: here 912 | case SEEK_SET: | ^~~~ vim +911 fs/proc/base.c 903 904 loff_t mem_lseek(struct file *file, loff_t offset, int orig) 905 { 906 loff_t ret = 0; 907 908 spin_lock(&file->f_lock); 909 switch (orig) { 910 case SEEK_CUR: > 911 offset += file->f_pos; 912 case SEEK_SET: 913 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ 914 if ((unsigned long long)offset >= -MAX_ERRNO) 915 ret = -EOVERFLOW; 916 break; 917 default: 918 ret = -EINVAL; 919 } 920 if (!ret) { 921 if (offset < 0 && !(unsigned_offsets(file))) { 922 ret = -EINVAL; 923 } else { 924 file->f_pos = offset; 925 ret = file->f_pos; 926 force_successful_syscall_return(); 927 } 928 } 929 930 spin_unlock(&file->f_lock); 931 return ret; 932 } 933 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
