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

From: Daniel Borkmann
Date: Mon Nov 25 2019 - 18:43:21 EST


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/201911251639.UWS3hE3Y%lkp@xxxxxxxxx

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 <lkp@xxxxxxxxx>
Cc: Andrii Nakryiko <andriin@xxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>

Thanks for the patch, already fixed via:

https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=ed81745a4c96841937f1da35c0eb66ac312e1480