Hi Kumar,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on bpf-next/master]

url:    https://github.com/0day-ci/linux/commits/Kumar-Kartikeya-Dwivedi/Support-kernel-module-function-calls-from-eBPF/20210831-013531
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/5bc18bc51d4d66d55910a9829c2a6b0a5a6b61ea
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Kumar-Kartikeya-Dwivedi/Support-kernel-module-function-calls-from-eBPF/20210831-013531
        git checkout 5bc18bc51d4d66d55910a9829c2a6b0a5a6b61ea
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=um SUBARCH=x86_64 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 >>):

   /usr/bin/ld: net/ipv4/tcp_cubic.o: in function `cubictcp_unregister':
>> tcp_cubic.c:(.exit.text+0xd): undefined reference to `unregister_bpf_tcp_ca_kfunc_btf_set'
   /usr/bin/ld: net/ipv4/tcp_cubic.o: in function `cubictcp_register':
>> tcp_cubic.c:(.init.text+0x8e): undefined reference to `register_bpf_tcp_ca_kfunc_btf_set'
   /usr/bin/ld: kernel/bpf/core.o: in function `bpf_prog_free_deferred':
   core.c:(.text+0x7b0): undefined reference to `btf_put'
   collect2: error: ld returned 1 exit status

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0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org