From: Thomas Richter <[email protected]>
Date: Mon, 7 Aug 2017 10:16:36 +0200
> Commit 18f3d6be6be1 ("selftests/bpf: Add test cases to test narrower ctx
> field loads")
> introduced new eBPF test cases. One of them (test_pkt_md_access.c)
> fails on s390x. The BPF verifier error message is:
>
> [root@s8360046 bpf]# ./test_progs
> test_pkt_access:PASS:ipv4 349 nsec
> test_pkt_access:PASS:ipv6 212 nsec
> [....]
> libbpf: load bpf program failed: Permission denied
> libbpf: -- BEGIN DUMP LOG ---
> libbpf:
> 0: (71) r2 = *(u8 *)(r1 +0)
> invalid bpf_context access off=0 size=1
>
> libbpf: -- END LOG --
> libbpf: failed to load program 'test1'
> libbpf: failed to load object './test_pkt_md_access.o'
> Summary: 29 PASSED, 1 FAILED
> [root@s8360046 bpf]#
>
> This is caused by a byte endianness issue. S390x is a big endian
> architecture. Pointer access to the lowest byte or halfword of a
> four byte value need to add an offset.
> On little endian architectures this offset is not needed.
>
> Fix this and use the same approach as the originator used for other files
> (for example test_verifier.c) in his original commit.
>
> With this fix the test program test_progs succeeds on s390x:
...
> Signed-off-by: Thomas Richter <[email protected]>
> Acked-by: Daniel Borkmann <[email protected]>
Applied, thanks.
