On Fri, 29 Sep 2017 20:06:09 -0700
Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote:
> > +/*** Trace point code ***/
> > +
> > +/* Tracepoint format:
> > /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
> > + * Code in: kernel/include/trace/events/xdp.h
> > + */
> > +struct xdp_redirect_ctx {
> > + unsigned short common_type; // offset:0; size:2; signed:0;
> > + unsigned char common_flags; // offset:2; size:1; signed:0;
> > + unsigned char common_preempt_count;// offset:3; size:1; signed:0;
> > + int common_pid; // offset:4; size:4; signed:1;
>
> this part is not right. First 8 bytes are not accessible by bpf code.
> Please use __u64 pad; or similar here.
I've corrected this in V3.
Can you explain why BPF cannot access these (first 8 bytes) struct members?
> Just noticed that samples/bpf/xdp_monitor_kern.c has the same problem.
>
> > +
> > + int prog_id; // offset:8; size:4; signed:1;
> > + u32 act; // offset:12 size:4; signed:0;
> > + int ifindex; // offset:16 size:4; signed:1;
> > + int err; // offset:20 size:4; signed:1;
> > + int to_ifindex; // offset:24 size:4; signed:1;
> > + u32 map_id; // offset:28 size:4; signed:0;
> > + int map_index; // offset:32 size:4; signed:1;
> > +}; // offset:36
>
> the second part of fields is correct.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
