Switching to vmlinux.h definitions seems to make the verifier very unhappy with bitfield accesses. The error is: ; md.u.md2.dir = direction; 33: (69) r1 = *(u16 *)(r2 +11) misaligned stack access off (0x0; 0x0)+-64+11 size 2 It looks like disabling CO-RE relocations seem to make the error go away. Co-developed-by: Antony Antony <antony.antony@xxxxxxxxxxx> Signed-off-by: Antony Antony <antony.antony@xxxxxxxxxxx> Signed-off-by: Daniel Xu <dxu@xxxxxxxxx> --- tools/testing/selftests/bpf/progs/test_tunnel_kern.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c index 3065a716544d..ec7e04e012ae 100644 --- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c +++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c @@ -6,6 +6,7 @@ * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ +#define BPF_NO_PRESERVE_ACCESS_INDEX #include "vmlinux.h" #include <bpf/bpf_helpers.h> #include <bpf/bpf_endian.h> -- 2.42.1