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-disallo... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 82c5ba14c091497fc5d79ee017f962e50c3f69ac config: x86_64-rhel-7.6-kselftests (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(a)intel.com&gt; All errors (new ones prefixed by >>, old ones prefixed by <<): ld: arch/x86/entry/entry_64.o: in function `asm_exc_debug': ld: arch/x86/entry/entry_64.o: in function `paranoid_exit': ld: arch/x86/entry/entry_64.S:1290: undefined reference to `debug_stack_reset' Segmentation fault .btf.vmlinux.bin.o: file not recognized: file format not recognized vim +368 arch/x86/include/asm/idtentry.h b209b183b6db50 Thomas Gleixner 2020-02-25 366 c087b87b146916 Thomas Gleixner 2020-02-25 367 /* #DB */ c087b87b146916 Thomas Gleixner 2020-02-25 @368 DECLARE_IDTENTRY_DEBUG(X86_TRAP_DB, exc_debug); c087b87b146916 Thomas Gleixner 2020-02-25 369 DECLARE_IDTENTRY_XEN(X86_TRAP_DB, debug); c087b87b146916 Thomas Gleixner 2020-02-25 370 :::::: The code at line 368 was first introduced by commit :::::: c087b87b1469166dbb0d757c7d79fecf14a90a0a x86/entry: Convert Debug exception to IDTENTRY_DB :::::: TO: Thomas Gleixner <tglx(a)linutronix.de&gt; :::::: CC: Thomas Gleixner <tglx(a)linutronix.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org