On 02/10/2020 10:22 AM, Andrew Morton wrote: > On Thu, 6 Feb 2020 13:49:35 +0530 Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > >> >> On 02/06/2020 04:40 AM, kbuild test robot wrote: >>> Hi Anshuman, >>> >>> Thank you for the patch! Yet something to improve: >>> >>> [auto build test ERROR on powerpc/next] >>> [also build test ERROR on s390/features linus/master arc/for-next v5.5] >>> [cannot apply to mmotm/master tip/x86/core arm64/for-next/core next-20200205] >>> [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/Anshuman-Khandual/mm-debug-Add-tests-validating-architecture-page-table-helpers/20200205-215507 >>> base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next >>> config: ia64-allmodconfig (attached as .config) >>> compiler: ia64-linux-gcc (GCC) 7.5.0 >>> reproduce: >>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross >>> chmod +x ~/bin/make.cross >>> # save the attached .config to linux build tree >>> GCC_VERSION=7.5.0 make.cross ARCH=ia64 >>> >>> If you fix the issue, kindly add following tag >>> Reported-by: kbuild test robot <lkp@xxxxxxxxx> >>> >>> All error/warnings (new ones prefixed by >>): >>> >>> In file included from include/asm-generic/pgtable-nopud.h:8:0, >>> from arch/ia64/include/asm/pgtable.h:586, >>> from include/linux/mm.h:99, >>> from include/linux/highmem.h:8, >>> from mm/debug_vm_pgtable.c:14: >>> mm/debug_vm_pgtable.c: In function 'pud_clear_tests': >>>>> include/asm-generic/pgtable-nop4d-hack.h:47:32: error: implicit declaration of function '__pgd'; did you mean '__p4d'? [-Werror=implicit-function-declaration] >>> #define __pud(x) ((pud_t) { __pgd(x) }) >>> ^ >>>>> mm/debug_vm_pgtable.c:141:8: note: in expansion of macro '__pud' >>> pud = __pud(pud_val(pud) | RANDOM_ORVALUE); >>> ^~~~~ >>>>> include/asm-generic/pgtable-nop4d-hack.h:47:22: warning: missing braces around initializer [-Wmissing-braces] >>> #define __pud(x) ((pud_t) { __pgd(x) }) >>> ^ >>>>> mm/debug_vm_pgtable.c:141:8: note: in expansion of macro '__pud' >>> pud = __pud(pud_val(pud) | RANDOM_ORVALUE); >>> ^~~~~ >>> cc1: some warnings being treated as errors >> >> This build failure is expected now given that we have allowed DEBUG_VM_PGTABLE >> with EXPERT without platform requiring ARCH_HAS_DEBUG_VM_PGTABLE. This problem >> i.e build failure caused without a platform __pgd(), is known to exist both on >> ia64 and arm (32bit) platforms. Please refer https://lkml.org/lkml/2019/9/24/314 >> for details where this was discussed earlier. >> > > I'd prefer not to merge a patch which is known to cause build > regressions. Is there some temporary thing we can do to prevent these > errors until arch maintainers(?) get around to implementing the > long-term fixes? We could explicitly disable CONFIG_DEBUG_VM_PGTABLE on ia64 and arm platforms which will ensure that others can still use the EXPERT path. config DEBUG_VM_PGTABLE bool "Debug arch page table for semantics compliance" depends on MMU depends on !(IA64 || ARM) depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT default n if !ARCH_HAS_DEBUG_VM_PGTABLE default y if DEBUG_VM
