Re: [kbuild-all] [PATCH 6/6] sysctl: Add global tunable mt_page_copy

From: Anshuman Khandual
Date: Fri Mar 10 2017 - 07:45:43 EST

On 03/10/2017 06:42 AM, Ye Xiaolong wrote:
> On 03/08, Anshuman Khandual wrote:
>> On 02/17/2017 09:00 PM, kbuild test robot wrote:
>>> Hi Zi,
>>> [auto build test ERROR on linus/master]
>>> [also build test ERROR on v4.10-rc8 next-20170217]
>>> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>>> url:
>>> config: i386-randconfig-a0-02131010 (attached as .config)
>>> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
>> Though I dont have the same compiler, I am unable to reproduce this
>> build failure exactly. The build fails but for a different symbol.
> I think previous "undefined reference to `mt_page_copy'" error is due to kbuild
> bot didn't set CONFIG_MIGRATION (see attached config in original mail) since it
> is a randconfig test.

If CONFIG_MIGRATION is not set then mm/migrate.c never gets compiled
and the symbol 'mt_page_copy' is never exported for kernel/sysctl.c
based extern variable to use. Sure, will fix it by keeping all the
code in kernel/sysctl.c within CONFIG_MIGRATION config. Thanks for
pointing it out.