Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support
Date	2017-02-08 21:10 +0100
Message-ID	<t8GIW-4OC-27@gated-at.bofh.it> (permalink)
References	<t8Ee5-3aO-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed,  8 Feb 2017 11:24:56 -0600
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

>     # echo 'wakeup_latency lat=sched_switch:wakeup_lat \
>                            pid=sched_switch:woken_pid \
>                            prio=sched_switch:woken_prio' >> \
>             /sys/kernel/debug/tracing/synthetic_events

I applied all your patches, did the above and then:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000034
 IP: free_synthetic_event+0x46/0xb0
 PGD 0 
 
 Oops: 0000 [#1] SMP
 Modules linked in: ip6table_filter ip6_tables x86_pkg_temp_thermal kvm_intel kvm snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core irqbypass snd_seq snd_seq_device snd_pcm snd_timer snd i2c_i801 soundcore wmi i915 i2c_algo_bit drm_kms_helper e1000e syscopyarea sysfillrect sysimgblt fb_sys_fops ptp drm pps_core i2c_core video
 CPU: 0 PID: 1389 Comm: bash Not tainted 4.10.0-rc2-test+ #36
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
 task: ffff8800c8c48000 task.stack: ffffc90000a00000
 RIP: 0010:free_synthetic_event+0x46/0xb0
 RSP: 0018:ffffc90000a03cf8 EFLAGS: 00010282
 RAX: 0000000015675b00 RBX: ffff8800ccf4bcd0 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: ffffc90000a03d18 R08: 0000000000000000 R09: ffff8800ccea7c6c
 R10: 000000000000003d R11: ffff8800c8c48000 R12: 0000000000000001
 R13: ffff8800c8ca6000 R14: ffff8800ccea7d88 R15: 0000000000000001
 FS:  00007fde7acdb700(0000) GS:ffff88011ea00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000034 CR3: 00000000ccc44000 CR4: 00000000001406f0
 Call Trace:
  create_synthetic_event+0xcb/0x580
  ? parse_var_ref+0x120/0x120
  trace_run_command+0x5f/0x70
  trace_parse_run_command+0x76/0x150
  ? parse_var_ref+0x120/0x120
  synthetic_events_write+0x10/0x20
  __vfs_write+0x28/0x140
  ? vmacache_find+0xcc/0x180
  ? rw_verify_area+0xd8/0x190
  ? _cond_resched+0x2e/0x50
  ? __sb_start_write+0x82/0xe0
  vfs_write+0x138/0x260
  SyS_write+0x4f/0xa0
  entry_SYSCALL_64_fastpath+0x13/0x94


Anyway, I kinda like the approach. I'll go patch by patch to see what
you did and maybe even take a few now, if they seem appropriate as
helpers.

-- Steve

Thread

[RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:30 +0100
  [RFC][PATCH 06/21] tracing: Increase tracing map KEYS_MAX size Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:30 +0100
  [RFC][PATCH 08/21] tracing: Make traceprobe parsing code reusable Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:30 +0100
    Re: [RFC][PATCH 08/21] tracing: Make traceprobe parsing code  reusable Steven Rostedt <rostedt@goodmis.org> - 2017-02-09 22:00 +0100
  [RFC][PATCH 20/21] tracing: Add 'onmax' hist trigger action support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
  [RFC][PATCH 21/21] tracing: Add inter-event hist trigger Documentation Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
  [RFC][PATCH 17/21] tracing: Add hist trigger action hook Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
  [RFC][PATCH 01/21] tracing: Add hist_field_name() accessor Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
    Re: [RFC][PATCH 01/21] tracing: Add hist_field_name() accessor Steven Rostedt <rostedt@goodmis.org> - 2017-02-08 21:10 +0100
  [RFC][PATCH 13/21] tracing: Add simple expression support to hist triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
  [RFC][PATCH 19/21] tracing: Add 'onmatch' hist trigger action support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
  [RFC][PATCH 11/21] tracing: Add variable support to hist triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:40 +0100
    Re: [RFC][PATCH 11/21] tracing: Add variable support to hist triggers Namhyung Kim <namhyung@kernel.org> - 2017-02-13 07:10 +0100
  [RFC][PATCH 18/21] tracing: Add support for 'synthetic' events Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:50 +0100
  [RFC][PATCH 04/21] tracing: Give event triggers access to ring_buffer_event Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:50 +0100
  [RFC][PATCH 02/21] tracing: Reimplement log2 Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 18:50 +0100
    Re: [RFC][PATCH 02/21] tracing: Reimplement log2 Steven Rostedt <rostedt@goodmis.org> - 2017-02-08 21:20 +0100
      Re: [RFC][PATCH 02/21] tracing: Reimplement log2 Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-08 21:30 +0100
  Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Steven Rostedt <rostedt@goodmis.org> - 2017-02-08 21:10 +0100
    Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-09 00:30 +0100
      Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Steven Rostedt <rostedt@goodmis.org> - 2017-02-09 03:30 +0100
    Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-09 01:00 +0100
  Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Masami Hiramatsu <mhiramat@kernel.org> - 2017-02-09 00:20 +0100
    Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-09 02:20 +0100
      Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Masami Hiramatsu <mhiramat@kernel.org> - 2017-02-09 15:40 +0100
        Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-09 18:20 +0100
          Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Steven Rostedt <rostedt@goodmis.org> - 2017-02-09 21:00 +0100
      Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support fche@redhat.com (Frank Ch. Eigler) - 2017-02-09 17:10 +0100
        Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-09 19:50 +0100
  Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Namhyung Kim <namhyung@kernel.org> - 2017-02-10 05:20 +0100
    Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Masami Hiramatsu <mhiramat@kernel.org> - 2017-02-10 12:50 +0100
      Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-10 20:00 +0100
        Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Namhyung Kim <namhyung@kernel.org> - 2017-02-13 02:10 +0100
    Re: [RFC][PATCH 00/21] tracing: Inter-event (e.g. latency) support Tom Zanussi <tom.zanussi@linux.intel.com> - 2017-02-10 19:50 +0100

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