Hi Jordan, kernel test robot noticed the following build warnings: [auto build test WARNING on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Jordan-Rome/bpf-Add-tests-for-bpf_copy_from_user_str-kfunc/20240814-232043 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/20240814004531.352157-1-linux%40jordanrome.com patch subject: [bpf-next v4 1/2] bpf: Add bpf_copy_from_user_str kfunc config: x86_64-buildonly-randconfig-002-20240815 (https://download.01.org/0day-ci/archive/20240815/202408150928.HuDSmPPF-lkp@xxxxxxxxx/config) compiler: gcc-11 (Debian 11.3.0-12) 11.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240815/202408150928.HuDSmPPF-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/202408150928.HuDSmPPF-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): kernel/bpf/helpers.c: In function 'bpf_copy_from_user_str': >> kernel/bpf/helpers.c:2972:20: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else] 2972 | if (ret <= count) | ^ vim +/else +2972 kernel/bpf/helpers.c 2941 2942 /** 2943 * bpf_copy_from_user_str() - Copy a string from an unsafe user address 2944 * @dst: Destination address, in kernel space. This buffer must be at 2945 * least @dst__szk bytes long. 2946 * @dst__szk: Maximum number of bytes to copy, including the trailing NUL. 2947 * @unsafe_ptr__ign: Source address, in user space. 2948 * @flags: The only supported flag is BPF_ZERO_BUFFER 2949 * 2950 * Copies a NUL-terminated string from userspace to BPF space. If user string is 2951 * too long this will still ensure zero termination in the dst buffer unless 2952 * buffer size is 0. 2953 * 2954 * If BPF_ZERO_BUFFER flag is set, memset the tail of @dst to 0 on success. 2955 */ 2956 __bpf_kfunc int bpf_copy_from_user_str(void *dst, u32 dst__szk, const void __user *unsafe_ptr__ign, u64 flags) 2957 { 2958 int ret; 2959 int count; 2960 2961 if (unlikely(!dst__szk)) 2962 return 0; 2963 2964 count = dst__szk - 1; 2965 if (unlikely(!count)) { 2966 ((char *)dst)[0] = '\0'; 2967 return 1; 2968 } 2969 2970 ret = strncpy_from_user(dst, unsafe_ptr__ign, count); 2971 if (ret >= 0) { > 2972 if (ret <= count) 2973 if (flags & BPF_ZERO_BUFFER) 2974 memset((char *)dst + ret, 0, dst__szk - ret); 2975 else 2976 ((char *)dst)[ret] = '\0'; 2977 ret++; 2978 } 2979 2980 return ret; 2981 } 2982 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
