Hi Peter,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on tip/auto-latest]
[cannot apply to tip/x86/core luto/next v5.7-rc7 next-20200522]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Peter-Zijlstra/x86-entry-disallow-DB-more/20200523-045236
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 82c5ba14c091497fc5d79ee017f962e50c3f69ac
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build):
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

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

All errors (new ones prefixed by >>, old ones prefixed by <<):

ld: arch/x86/entry/entry_64.o: in function `asm_exc_debug':
>> (.entry.text+0xb32): undefined reference to `debug_stack_set_zero'
>> ld: (.entry.text+0xb3c): undefined reference to `debug_stack_reset'
ld: arch/x86/entry/entry_64.o: in function `paranoid_exit':
(.entry.text+0x1247): undefined reference to `debug_stack_set_zero'
ld: (.entry.text+0x1251): undefined reference to `debug_stack_reset'
>> ld: (.entry.text+0x12b3): undefined reference to `debug_stack_set_zero'
ld: (.entry.text+0x12bd): undefined reference to `debug_stack_reset'

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