Hi Rocco,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on net-next/master]
[also build test ERROR on net/master linus/master v5.12 next-20210429]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rocco-Yue/rtnetlink-add-rtnl_lock-debug-log/20210429-151958
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 4a52dd8fefb45626dace70a63c0738dbd83b7edb
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/662e06d6ff200b5cee31d3615a7b2a5079cc5c0a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rocco-Yue/rtnetlink-add-rtnl_lock-debug-log/20210429-151958
        git checkout 662e06d6ff200b5cee31d3615a7b2a5079cc5c0a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=m68k 

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 >>):

   m68k-linux-ld: kernel/stacktrace.o: in function `stack_trace_save':
>> (.text+0x144): undefined reference to `save_stack_trace'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for STACKTRACE
   Depends on STACKTRACE_SUPPORT
   Selected by
   - RTNL_LOCK_DEBUG

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