netdev - Re: [PATCH bpf-next v6 3/6] bpf: Allow helpers to accept pointers with a fixed size

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Date:   Sat, 23 Apr 2022 16:38:54 +0800
From:   kernel test robot <lkp@...el.com>
To:     Maxim Mikityanskiy <maximmi@...dia.com>, bpf@...r.kernel.org,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, netdev@...r.kernel.org
Cc:     kbuild-all@...ts.01.org, Tariq Toukan <tariqt@...dia.com>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Petar Penkov <ppenkov@...gle.com>,
        Lorenz Bauer <lmb@...udflare.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        David Ahern <dsahern@...nel.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Joe Stringer <joe@...ium.io>,
        Florent Revest <revest@...omium.org>,
        linux-kselftest@...r.kernel.org,
        Toke Høiland-Jørgensen <toke@...e.dk>,
        Kumar Kartikeya Dwivedi <memxor@...il.com>,
        Florian Westphal <fw@...len.de>, pabeni@...hat.com,
        Maxim Mikityanskiy <maximmi@...dia.com>
Subject: Re: [PATCH bpf-next v6 3/6] bpf: Allow helpers to accept pointers
 with a fixed size

Hi Maxim,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Maxim-Mikityanskiy/bpf-Use-ipv6_only_sock-in-bpf_tcp_gen_syncookie/20220423-022511
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: arc-randconfig-r036-20220422 (https://download.01.org/0day-ci/archive/20220423/202204231646.yQjLArUK-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 11.2.0
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
        # https://github.com/intel-lab-lkp/linux/commit/e374c2f19a674b586212d155ecb708aaa86dcd2c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Maxim-Mikityanskiy/bpf-Use-ipv6_only_sock-in-bpf_tcp_gen_syncookie/20220423-022511
        git checkout e374c2f19a674b586212d155ecb708aaa86dcd2c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

   kernel/bpf/verifier.c: In function 'check_helper_call':
>> kernel/bpf/verifier.c:5954:49: warning: array subscript 5 is above array bounds of 'const enum bpf_arg_type[5]' [-Warray-bounds]
    5954 |         return arg_type_is_mem_size(fn->arg_type[arg + 1]) || fn->arg_size[arg];
         |                                     ~~~~~~~~~~~~^~~~~~~~~
   In file included from include/linux/bpf-cgroup.h:5,
                    from kernel/bpf/verifier.c:7:
   include/linux/bpf.h:456:35: note: while referencing 'arg_type'
     456 |                 enum bpf_arg_type arg_type[5];
         |                                   ^~~~~~~~
   kernel/bpf/verifier.c:5952:57: warning: array subscript 5 is above array bounds of 'const enum bpf_arg_type[5]' [-Warray-bounds]
    5952 |                 return arg_type_is_mem_size(fn->arg_type[arg + 1]) ==
         |                                             ~~~~~~~~~~~~^~~~~~~~~
   In file included from include/linux/bpf-cgroup.h:5,
                    from kernel/bpf/verifier.c:7:
   include/linux/bpf.h:456:35: note: while referencing 'arg_type'
     456 |                 enum bpf_arg_type arg_type[5];
         |                                   ^~~~~~~~


vim +5954 kernel/bpf/verifier.c

  5948	
  5949	static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
  5950	{
  5951		if (arg_type_is_mem_ptr(fn->arg_type[arg]))
  5952			return arg_type_is_mem_size(fn->arg_type[arg + 1]) ==
  5953				!!fn->arg_size[arg];
> 5954		return arg_type_is_mem_size(fn->arg_type[arg + 1]) || fn->arg_size[arg];
  5955	}
  5956	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp