The error code -EACCES is returned when bpf prog is tested in 32-bit arch. This is because bpf_object__relocate modifies instruction to change memory size to 4 bytes, as shown in the following messages: libbpf: prog 'kfunc_call_test1': relo #2: matching candidate #0 <byte_off> [18342] struct __sk_buff.sk (0:30:0 @ offset 168) libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) off 168 -> 168 libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) mem_sz 8 -> 4 As a result, the bpf_skb_is_valid_access check fails, for 32-bit arch, adjust check sk size. Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx> --- net/core/filter.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index bb0136e7a8e4..47cbad2e609f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -8269,7 +8269,13 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type return false; break; case offsetof(struct __sk_buff, sk): - if (type == BPF_WRITE || size != sizeof(__u64)) + /* CO_RE adjusts pointer accesses from 8-byte read to + * 4-byte reads in 32-bit host arch, so 32-bit can only + * read the 32-bit pointer or the full 64-bit value, + * and 64-bit can read write the 64-bit pointer. + */ + if (type == BPF_WRITE || + (size != sizeof(struct bpf_sock *) && size != sizeof(__u64))) return false; info->reg_type = PTR_TO_SOCK_COMMON_OR_NULL; break; -- 2.30.GIT
