From: Thomas Richter <redacted>
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 <redacted>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Applied, thanks.