Messages in this thread | | | Date | Sun, 29 Oct 2023 17:22:02 -0600 | From | Daniel Xu <> | Subject | Re: [RFC bpf-next 5/6] bpf: selftests: test_tunnel: Disable CO-RE relocations |
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On Fri, Oct 27, 2023 at 01:33:09PM -0700, Andrii Nakryiko wrote: > On Fri, Oct 27, 2023 at 11:46 AM Daniel Xu <dxu@dxuuu.xyz> 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
In this case the code in question is:
__u8 direction = 0; md.u.md2.dir = direction;
IOW the problem is assigning to bitfields, not reading from them.
Is that something that libbpf needs to support as well?
Thanks, Daniel
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