s390x cache line size is 256 bytes, so skb_shared_info must be aligned on a much larger boundary than for x86. This makes the maximum packet size smaller. Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> --- tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c index a50971c6cf4a..ac70e871d62f 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c @@ -65,7 +65,11 @@ static int attach_tc_prog(struct bpf_tc_hook *hook, int fd) /* The maximum permissible size is: PAGE_SIZE - sizeof(struct xdp_page_head) - * sizeof(struct skb_shared_info) - XDP_PACKET_HEADROOM = 3368 bytes */ +#if defined(__s390x__) +#define MAX_PKT_SIZE 3176 +#else #define MAX_PKT_SIZE 3368 +#endif static void test_max_pkt_size(int fd) { char data[MAX_PKT_SIZE + 1] = {}; -- 2.39.1