[PATCH RESEND bpf-next 15/18] bpf: take into account BPF token when fetching helper protos

[Andrii Nakryiko]

On Fri, Jun 2, 2023 at 11:48 AM kernel test robot <lkp at intel.com> wrote:
>
> Hi Andrii,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on bpf-next/master]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/bpf-introduce-BPF-token-object/20230602-230448
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
> patch link:    https://lore.kernel.org/r/20230602150011.1657856-16-andrii%40kernel.org
> patch subject: [PATCH RESEND bpf-next 15/18] bpf: take into account BPF token when fetching helper protos
> config: um-x86_64_defconfig (https://download.01.org/0day-ci/archive/20230603/202306030252.UOXkWZTK-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build):
>         # https://github.com/intel-lab-lkp/linux/commit/3d830ca845b075ab4132487aaaa69b70a467863c
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Andrii-Nakryiko/bpf-introduce-BPF-token-object/20230602-230448
>         git checkout 3d830ca845b075ab4132487aaaa69b70a467863c
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         make W=1 O=build_dir ARCH=um SUBARCH=x86_64 olddefconfig
>         make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp at intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202306030252.UOXkWZTK-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>    In file included from include/linux/bpf_verifier.h:7,
>                     from net/core/filter.c:21:
>    include/linux/bpf.h: In function 'bpf_token_new_fd':
>    include/linux/bpf.h:2475:16: warning: returning 'int' from a function with return type 'struct bpf_token *' makes pointer from integer without a cast [-Wint-conversion]
>     2475 |         return -EOPNOTSUPP;
>          |                ^

bad copy/paste, this function should return int. I forgot to test that
everything compiles without CONFIG_BPF_SYSCALL.


>    net/core/filter.c: In function 'bpf_sk_base_func_proto':
> >> net/core/filter.c:11653:14: error: implicit declaration of function 'bpf_token_capable'; did you mean 'bpf_token_put'? [-Werror=implicit-function-declaration]
>    11653 |         if (!bpf_token_capable(prog->aux->token, CAP_PERFMON))
>          |              ^~~~~~~~~~~~~~~~~
>          |              bpf_token_put
>    cc1: some warnings being treated as errors
>
>

hm.. maybe I'll just make bpf_token_capable() a static inline function
in include/linux/bpf.h

> vim +11653 net/core/filter.c
>
>  11619
>  11620  static const struct bpf_func_proto *
>  11621  bpf_sk_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
>  11622  {
>  11623          const struct bpf_func_proto *func;
>  11624
>  11625          switch (func_id) {
>  11626          case BPF_FUNC_skc_to_tcp6_sock:
>  11627                  func = &bpf_skc_to_tcp6_sock_proto;
>  11628                  break;
>  11629          case BPF_FUNC_skc_to_tcp_sock:
>  11630                  func = &bpf_skc_to_tcp_sock_proto;
>  11631                  break;
>  11632          case BPF_FUNC_skc_to_tcp_timewait_sock:
>  11633                  func = &bpf_skc_to_tcp_timewait_sock_proto;
>  11634                  break;
>  11635          case BPF_FUNC_skc_to_tcp_request_sock:
>  11636                  func = &bpf_skc_to_tcp_request_sock_proto;
>  11637                  break;
>  11638          case BPF_FUNC_skc_to_udp6_sock:
>  11639                  func = &bpf_skc_to_udp6_sock_proto;
>  11640                  break;
>  11641          case BPF_FUNC_skc_to_unix_sock:
>  11642                  func = &bpf_skc_to_unix_sock_proto;
>  11643                  break;
>  11644          case BPF_FUNC_skc_to_mptcp_sock:
>  11645                  func = &bpf_skc_to_mptcp_sock_proto;
>  11646                  break;
>  11647          case BPF_FUNC_ktime_get_coarse_ns:
>  11648                  return &bpf_ktime_get_coarse_ns_proto;
>  11649          default:
>  11650                  return bpf_base_func_proto(func_id, prog);
>  11651          }
>  11652
>  11653          if (!bpf_token_capable(prog->aux->token, CAP_PERFMON))
>  11654                  return NULL;
>  11655
>  11656          return func;
>  11657  }
>  11658
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>