tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/batch
head:   b81b17307e02f8e6d4abf87e7ec2d7e5aea1e0b5
commit: 2c1de2c23766232f27faf7c1af1a892c83e89377 [16/27] bpf: Add bpf_trampoline_multi_get/put functions
config: i386-randconfig-a016-20210829 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?id=2c1de2c23766232f27faf7c1af1a892c83e89377
        git remote add jolsa-perf https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
        git fetch --no-tags jolsa-perf bpf/batch
        git checkout 2c1de2c23766232f27faf7c1af1a892c83e89377
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   ld: kernel/bpf/trampoline.o: in function `bpf_trampoline_compute_key':
>> include/linux/bpf_verifier.h:513: undefined reference to `btf_obj_id'
   ld: kernel/bpf/trampoline.o: in function `bpf_trampoline_multi_get':
>> kernel/bpf/trampoline.c:672: undefined reference to `bpf_check_attach_target'


vim +513 include/linux/bpf_verifier.h

ab3f0063c48c26 Jakub Kicinski         2017-11-03  500  
51c39bb1d5d105 Alexei Starovoitov     2020-01-09  501  int check_ctx_reg(struct bpf_verifier_env *env,
51c39bb1d5d105 Alexei Starovoitov     2020-01-09  502  		  const struct bpf_reg_state *reg, int regno);
e5069b9c23b385 Dmitrii Banshchikov    2021-02-13  503  int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
e5069b9c23b385 Dmitrii Banshchikov    2021-02-13  504  		   u32 regno, u32 mem_size);
51c39bb1d5d105 Alexei Starovoitov     2020-01-09  505  
f7b12b6fea0098 Toke Høiland-Jørgensen 2020-09-25  506  /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
f7b12b6fea0098 Toke Høiland-Jørgensen 2020-09-25  507  static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
22dc4a0f5ed11b Andrii Nakryiko        2020-12-03  508  					     struct btf *btf, u32 btf_id)
f7b12b6fea0098 Toke Høiland-Jørgensen 2020-09-25  509  {
22dc4a0f5ed11b Andrii Nakryiko        2020-12-03  510  	if (tgt_prog)
22dc4a0f5ed11b Andrii Nakryiko        2020-12-03  511  		return ((u64)tgt_prog->aux->id << 32) | btf_id;
22dc4a0f5ed11b Andrii Nakryiko        2020-12-03  512  	else
22dc4a0f5ed11b Andrii Nakryiko        2020-12-03 @513  		return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id;
f7b12b6fea0098 Toke Høiland-Jørgensen 2020-09-25  514  }
f7b12b6fea0098 Toke Høiland-Jørgensen 2020-09-25  515  

:::::: The code at line 513 was first introduced by commit
:::::: 22dc4a0f5ed11b6dc8fd73a0892fa0ea1a4c3cdf bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier

:::::: TO: Andrii Nakryiko <andrii@kernel.org>
:::::: CC: Alexei Starovoitov <ast@kernel.org>

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