Re: [PATCH net-next] bpf: fix verifier issue at check_packet_ptr_add

[Daniel Borkmann]

On 02/03/2017 06:31 AM, William Tu wrote:
[...]

Yes, this is auto-generated. We want to use P4 2016 as front end to
generate ebpf for XDP.

[...]

R2 is no longer pkt_end, it's R2 == R0 == 0
269: (bf) r2 = r0
270: (77) r2 >>= 3
271: (bf) r4 = r1
272: (0f) r4 += r2

So at line 272, it's pkt_ptr = pkt_ptr + 0
thus the following fix works for us.
-               if (imm <= 0) {
+               if (imm < 0) {

Okay, makes sense. I'll wait with ACK for your respin with kselftest
case.

Thanks,
Daniel