Re: [linux-next:master 2890/4758] ld.lld: error: undefined symbol: phys_to_target_node

[Randy Dunlap <rdunlap@infradead.org>]

On 9/3/20 5:31 AM, Joao Martins wrote:
> On 9/3/20 6:49 AM, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head:   4442749a203151a319a5bb8d0b983b84253a6931
>> commit: bd295a352cfa24e5110a53f978edb48b7c21ff8f [2890/4758] ACPI: HMAT: attach a device for each soft-reserved range
>> config: x86_64-randconfig-a002-20200902 (attached as .config)
>> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 224d8153b53b16cf535ea1a55afdfe1ec5b1374f)
>> 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
>>         # install x86_64 cross compiling tool for clang build
>>         # apt-get install binutils-x86-64-linux-gnu
>>         git checkout bd295a352cfa24e5110a53f978edb48b7c21ff8f
>>         # save the attached .config to linux build tree
>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 
>>
>> 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 >>):
>>
>>>> ld.lld: error: undefined symbol: phys_to_target_node
>>    >>> referenced by device.c:84 (drivers/dax/hmem/device.c:84)
>>    >>>               dax/hmem/device.o:(hmem_register_one) in archive drivers/built-in.a
>>
> This would require the proposed fix below the scissors mark.
> 
> I had reported this failure before, but it needed an adjustment so I'm re-sending it.
> 
> --------------------------->8----------------------------
> 
> From 622c1297b7d76a319b07a29192fe9bfe5c2b6b7c Mon Sep 17 00:00:00 2001
> From: Joao Martins <joao.m.martins@oracle.com>
> Date: Tue, 1 Sep 2020 08:06:35 -0400
> Subject: [PATCH] device-dax: Require NUMA_KEEP_MEMINFO for
>  phys_to_target_node()
> 
> phys_to_target_node() and memory_add_physaddr_to_nid() are only defined
> with both CONFIG_NUMA=y and CONFIG_MEMORY_HOTPLUG=y.  Oherwise we see:
> 
> drivers/dax/hmem/device.o: in function `hmem_register_one':
> drivers/dax/hmem/device.c:85: undefined reference to `phys_to_target_node'
> 
> lkp also reports such build failures:
> 
> ld.lld: error: undefined symbol: phys_to_target_node
> 
> X86 is a special case in which both can be defined without depending on
> MEMORY_HOTPLUG=y. The other case is powerpc (for
> memory_add_physaddr_to_nid) but like ARM64 dependencies, the
> arch-specific override requires CONFIG_NUMA and CONFIG_MEMORY_HOTPLUG.
> 
> In all cases this ends up depending on CONFIG_NUMA_KEEP_MEMINFO to
> signal the presence of phys_to_target_node() which is what
> CONFIG_DEV_DAX_HMEM_DEVICES should depend on. Additionally, the X86
> arch-override is not selected unless X86_PMEM_LEGACY=y. So on
> CONFIG_DEV_DAX_HMEM we select CONFIG_NUMA_KEEP_INFO ourselves if both
> NUMA and X86 are set.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  drivers/dax/Kconfig | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
> index a66dff78f298..567428e10b7b 100644
> --- a/drivers/dax/Kconfig
> +++ b/drivers/dax/Kconfig
> @@ -35,6 +35,7 @@ config DEV_DAX_PMEM
>  config DEV_DAX_HMEM
>         tristate "HMEM DAX: direct access to 'specific purpose' memory"
>         depends on EFI_SOFT_RESERVE
> +       select NUMA_KEEP_MEMINFO if (NUMA && X86)
>         default DEV_DAX
>         help
>           EFI 2.8 platforms, and others, may advertise 'specific purpose'
> @@ -49,6 +50,7 @@ config DEV_DAX_HMEM
>           Say M if unsure.
> 
>  config DEV_DAX_HMEM_DEVICES
> +       depends on NUMA_KEEP_MEMINFO # for phys_to_target_node()
>         depends on DEV_DAX_HMEM && DAX=y
>         def_bool y
> 

Hi,

There is also this patch from Matt Fleming from last year that I have
successfully tested (built) on ppc64 and arch/sh/, where build errors were reported.

https://lore.kernel.org/lkml/20191223164220.GA14394@codeblueprint.co.uk/

but Matt doesn't seem to be replying to any emails about this patch...

-- 
~Randy