bpf, arm64: Feed byte-offset into bpf line info

insn_to_jit_off passed to bpf_prog_fill_jited_linfo() is calculated in
instruction granularity instead of bytes granularity, but BPF line info
requires byte offset.

bpf_prog_fill_jited_linfo() will be the last user of ctx.offset before
it is freed, so convert the offset into byte-offset before calling into
bpf_prog_fill_jited_linfo() in order to fix the line info dump on arm64.

Fixes: 37ab566 ("bpf: arm64: Enable arm64 jit to provide bpf_line_info")
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220226121906.5709-3-houtao1@huawei.com

arch/arm64/net/bpf_jit_comp.c

@@ -1133,6 +1133,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	prog->jited_len = prog_size;
 
 	if (!prog->is_func || extra_pass) {
+		int i;
+
+		/* offset[prog->len] is the size of program */
+		for (i = 0; i <= prog->len; i++)
+			ctx.offset[i] *= AARCH64_INSN_SIZE;
 		bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
 out_off:
 		kfree(ctx.offset);