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From: Steven Rostedt <rostedt@goodmis.org>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Jiri Olsa <jolsa@redhat.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	linux-api@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 linux-trace 4/8] samples: bpf: simple tracing example in C
Date: Mon, 9 Feb 2015 23:12:16 -0500	[thread overview]
Message-ID: <20150209231216.1b60f0cd@grimm.local.home> (raw)
In-Reply-To: <1423539961-21792-5-git-send-email-ast@plumgrid.com>

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

WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>
To: Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
Cc: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Namhyung Kim <namhyung-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Arnaldo Carvalho de Melo
	<acme-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
	Jiri Olsa <jolsa-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Masami Hiramatsu
	<masami.hiramatsu.pt-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v3 linux-trace 4/8] samples: bpf: simple tracing example in C
Date: Mon, 9 Feb 2015 23:12:16 -0500	[thread overview]
Message-ID: <20150209231216.1b60f0cd@grimm.local.home> (raw)
In-Reply-To: <1423539961-21792-5-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>

On Mon,  9 Feb 2015 19:45:57 -0800
Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org> 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

  parent reply	other threads:[~2015-02-10  4:11 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-10  3:45 [PATCH v3 linux-trace 0/8] tracing: attach eBPF programs to tracepoints/syscalls/kprobe Alexei Starovoitov
2015-02-10  3:45 ` Alexei Starovoitov
2015-02-10  3:45 ` [PATCH v3 linux-trace 1/8] tracing: attach eBPF programs to tracepoints and syscalls Alexei Starovoitov
2015-02-10  3:45   ` Alexei Starovoitov
2015-02-10  4:46   ` Steven Rostedt
2015-02-10  4:46     ` Steven Rostedt
2015-02-10  5:13   ` Steven Rostedt
2015-02-10  5:13     ` Steven Rostedt
2015-02-10  3:45 ` [PATCH v3 linux-trace 2/8] tracing: allow eBPF programs to call ktime_get_ns() Alexei Starovoitov
2015-02-10  3:45 ` [PATCH v3 linux-trace 3/8] samples: bpf: simple tracing example in eBPF assembler Alexei Starovoitov
2015-02-10  3:45 ` [PATCH v3 linux-trace 4/8] samples: bpf: simple tracing example in C Alexei Starovoitov
2015-02-10  4:08   ` Steven Rostedt
2015-02-10  5:16     ` Steven Rostedt
2015-02-10  5:16       ` Steven Rostedt
2015-02-10  5:45       ` Alexei Starovoitov
2015-02-10  5:47         ` Alexei Starovoitov
2015-02-10  5:47           ` Alexei Starovoitov
2015-02-10 12:27           ` Steven Rostedt
2015-02-10 12:27             ` Steven Rostedt
2015-02-10 12:24         ` Steven Rostedt
2015-02-10 12:24           ` Steven Rostedt
2015-02-10  4:12   ` Steven Rostedt [this message]
2015-02-10  4:12     ` Steven Rostedt
2015-02-10  3:45 ` [PATCH v3 linux-trace 5/8] samples: bpf: counting example for kfree_skb tracepoint and write syscall Alexei Starovoitov
2015-02-10  3:45   ` Alexei Starovoitov
2015-02-10  3:45 ` [PATCH v3 linux-trace 6/8] samples: bpf: IO latency analysis (iosnoop/heatmap) Alexei Starovoitov
2015-02-10  3:46 ` [PATCH v3 linux-trace 7/8] tracing: attach eBPF programs to kprobe/kretprobe Alexei Starovoitov
2015-02-10  3:46 ` [PATCH v3 linux-trace 8/8] samples: bpf: simple kprobe example Alexei Starovoitov
2015-02-10 14:55 ` [PATCH v3 linux-trace 0/8] tracing: attach eBPF programs to tracepoints/syscalls/kprobe Steven Rostedt
2015-02-10 14:55   ` Steven Rostedt

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