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SubjectRe: [PATCH v3 linux-trace 4/8] samples: bpf: simple tracing example in C
On Mon,  9 Feb 2015 19:45:57 -0800
Alexei Starovoitov <ast@plumgrid.com> wrote:

> +static void print_netif_receive_skb(void *data, int size)
> +{
> + struct ftrace_raw_netif_receive_skb {
> + struct trace_entry t;
> + void *skb;
> + __u32 len;
> + __u32 name;
> + } *e = data;

Same here, there's no guarantee that this structure will always match.

cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/format
name: netif_receive_skb
ID: 975
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;

field:void * skbaddr; offset:8; size:8; signed:0;
field:unsigned int len; offset:16; size:4; signed:0;
field:__data_loc char[] name; offset:20; size:4; signed:1;

print fmt: "dev=%s skbaddr=%p len=%u", __get_str(name), REC->skbaddr, REC->len

-- Steve


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