Re: [PATCH bpf-next 2/2] bpf: Add BPF_CALL_FUNC* to simplify code

[kernel test robot <lkp@intel.com>]

Hi Tao,

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/Tao-Chen/bpf-Add-BPF_CALL_FUNC-to-simplify-code/20240920-233936
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20240920153706.919154-1-chen.dylane%40gmail.com
patch subject: [PATCH bpf-next 2/2] bpf: Add BPF_CALL_FUNC* to simplify code
config: mips-mtx1_defconfig (https://download.01.org/0day-ci/archive/20240923/202409230306.7OGURpiH-lkp@intel.com/config)
compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240923/202409230306.7OGURpiH-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409230306.7OGURpiH-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/bpf/core.c:2010:36: error: called object type 'u8 *' (aka 'unsigned char *') is not a function or function pointer
                   BPF_R0 = BPF_CALL_FUNC(insn->imm)(BPF_R1, BPF_R2, BPF_R3,
                            ~~~~~~~~~~~~~~~~~~~~~~~~^
   kernel/bpf/core.c:2015:41: error: called object type 'u8 *' (aka 'unsigned char *') is not a function or function pointer
                   BPF_R0 = BPF_CALL_FUNC_ARGS(insn->imm)(BPF_R1, BPF_R2,
                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
   In file included from kernel/bpf/core.c:3079:
   In file included from include/linux/bpf_trace.h:5:
   In file included from include/trace/events/xdp.h:427:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:7:
>> include/linux/poll.h:136:27: warning: division by zero is undefined [-Wdivision-by-zero]
                   M(RDNORM) | M(RDBAND) | M(WRNORM) | M(WRBAND) |
                                           ^~~~~~~~~
   include/linux/poll.h:134:32: note: expanded from macro 'M'
   #define M(X) (__force __poll_t)__MAP(val, POLL##X, (__force __u16)EPOLL##X)
                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/poll.h:120:51: note: expanded from macro '__MAP'
           (from < to ? (v & from) * (to/from) : (v & from) / (from/to))
                                                            ^ ~~~~~~~~~
   include/linux/poll.h:136:39: warning: division by zero is undefined [-Wdivision-by-zero]
                   M(RDNORM) | M(RDBAND) | M(WRNORM) | M(WRBAND) |
                                                       ^~~~~~~~~
   include/linux/poll.h:134:32: note: expanded from macro 'M'
   #define M(X) (__force __poll_t)__MAP(val, POLL##X, (__force __u16)EPOLL##X)
                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/poll.h:120:51: note: expanded from macro '__MAP'
           (from < to ? (v & from) * (to/from) : (v & from) / (from/to))
                                                            ^ ~~~~~~~~~
   2 warnings and 2 errors generated.


vim +136 include/linux/poll.h

7a163b2195cda0 Al Viro 2018-02-01  131  
7a163b2195cda0 Al Viro 2018-02-01  132  static inline __poll_t demangle_poll(u16 val)
7a163b2195cda0 Al Viro 2018-02-01  133  {
7a163b2195cda0 Al Viro 2018-02-01  134  #define M(X) (__force __poll_t)__MAP(val, POLL##X, (__force __u16)EPOLL##X)
7a163b2195cda0 Al Viro 2018-02-01  135  	return M(IN) | M(OUT) | M(PRI) | M(ERR) | M(NVAL) |
7a163b2195cda0 Al Viro 2018-02-01 @136  		M(RDNORM) | M(RDBAND) | M(WRNORM) | M(WRBAND) |
7a163b2195cda0 Al Viro 2018-02-01  137  		M(HUP) | M(RDHUP) | M(MSG);
7a163b2195cda0 Al Viro 2018-02-01  138  #undef M
7a163b2195cda0 Al Viro 2018-02-01  139  }
7a163b2195cda0 Al Viro 2018-02-01  140  #undef __MAP
7a163b2195cda0 Al Viro 2018-02-01  141  
7a163b2195cda0 Al Viro 2018-02-01  142  

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