On Fri, Oct 27, 2023 at 11:46 AM Daniel Xu <dxu@xxxxxxxxx> wrote: > > 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. > for accessing bitfields libbpf provides BPF_CORE_READ_BITFIELD_PROBED() and BPF_CORE_READ_BITFIELD() macros > 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> > -- > 2.42.0 >
