Subject: Re: [PATCH] bpf: fix a no-mmu build failure by providing a stub allocator

From: John Hubbard <[email-masked]>
Date: Mon, 25 Nov 2019 15:45:17 -0800

On 11/25/19 3:43 PM, Daniel Borkmann wrote:
> On 11/26/19 12:41 AM, John Hubbard wrote:
>> Commit fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
>> added code that calls vmalloc_user_node_flags() and therefore requires
>> mm/vmalloc.c. However, that file is not built for the !CONFIG_MMU case.
>> This leads to a build failure when using ARM with the config provided
>> by at least one particular kbuild test robot report [1].
>>
>> [1] https://lore/kernel.org/r/[email-masked]
>>
>> Fix the build by providing a stub function for __bpf_map_area_alloc().
>>
>> Fixes: fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
>> Reported-by: kbuild test robot <[email-masked]>
>> Cc: Andrii Nakryiko <[email-masked]>
>> Cc: Daniel Borkmann <[email-masked]>
>> Cc: Song Liu <[email-masked]>
>> Cc: John Fastabend <[email-masked]>
>> Cc: Johannes Weiner <[email-masked]>
>> Signed-off-by: John Hubbard <[email-masked]>
> 
> Thanks for the patch, already fixed via:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=ed81745a4c96841937f1da35c0eb66ac312e1480

OK, good, that's a better fix, too. Appreciate the quick answers!

thanks,
-- 
John Hubbard
NVIDIA