Hi Yuanchu, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 521a547ced6477c54b4b0cc206000406c221b4d6 commit: 678f0cdc572c5fda940cb038d70eebb8d818adc8 selftests/damon: add damon to selftests root Makefile date: 5 months ago compiler: gcc-11 (Debian 11.3.0-5) 11.3.0 reproduce: # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=678f0cdc572c5fda940cb038d70eebb8d818adc8 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 678f0cdc572c5fda940cb038d70eebb8d818adc8 make O=/tmp/kselftest headers make O=/tmp/kselftest -C tools/testing/selftests If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot All warnings (new ones prefixed by >>): huge_count_read_write.c: In function 'write_read_with_huge_count': >> huge_count_read_write.c:23:9: warning: 'write' reading 4294967295 bytes from a region of size 1 [-Wstringop-overread] 23 | write(filedesc, "", 0xfffffffful); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from huge_count_read_write.c:8: /usr/include/unistd.h:367:16: note: in a call to function 'write' declared with attribute 'access (read_only, 2, 3)' 367 | extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur | ^~~~~ >> huge_count_read_write.c:25:15: warning: 'read' writing 4294967295 bytes into a region of size 25 overflows the destination [-Wstringop-overflow=] 25 | ret = read(filedesc, buf, 0xfffffffful); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ huge_count_read_write.c:14:14: note: destination object 'buf' of size 25 14 | char buf[25]; | ^~~ In file included from huge_count_read_write.c:8: /usr/include/unistd.h:360:16: note: in a call to function 'read' declared with attribute 'access (write_only, 2, 3)' 360 | extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur | ^~~~ -- 0-DAY CI Kernel Test Service https://01.org/lkp