Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper

On 06/05/2016 01:46 AM, kbuild test robot wrote:

Hi,

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Zi-Shen-Lim/arm64-bpf-implement-bpf_tail_call-helper/20160605-060435
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205
reproduce:
         wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
         chmod +x ~/bin/make.cross
         # save the attached .config to linux build tree
         make.cross ARCH=arm64

All errors (new ones prefixed by >>):

    In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
    include/linux/bpf.h: In function 'bpf_prog_get':

quoted

quoted

include/linux/bpf.h:235:9: error: implicit declaration of function 'ERR_PTR' [-Werror=implicit-function-declaration]

      return ERR_PTR(-EOPNOTSUPP);
             ^
    include/linux/bpf.h:235:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
    In file included from include/linux/rwsem.h:17:0,
                     from include/linux/mm_types.h:10,
                     from include/linux/sched.h:27,
                     from arch/arm64/include/asm/compat.h:25,
                     from arch/arm64/include/asm/stat.h:23,
                     from include/linux/stat.h:5,
                     from include/linux/compat.h:12,
                     from include/linux/filter.h:10,
                     from arch/arm64/net/bpf_jit_comp.c:22:
    include/linux/err.h: At top level:

quoted

quoted

include/linux/err.h:23:35: error: conflicting types for 'ERR_PTR'

     static inline void * __must_check ERR_PTR(long error)
                                       ^
    In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
    include/linux/bpf.h:235:9: note: previous implicit declaration of 'ERR_PTR' was here
      return ERR_PTR(-EOPNOTSUPP);
             ^
    cc1: some warnings being treated as errors

Looks like including linux/bpf.h at the very beginning causes issues when bpf
syscall is disabled. We should probably just include linux/err.h from bpf.h.