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From: Masami Hiramatsu <>
To: Masami Hiramatsu <>
Cc: Steven Rostedt <>,
	Ingo Molnar <>,
	"Naveen N . Rao" <>,
	Anil S Keshavamurthy <>,
	"David S . Miller" <>,,
Subject: Re: [PATCH 0/2] Enable new kprobe event at boot
Date: Wed, 22 May 2019 16:30:21 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Wed, 22 May 2019 00:39:32 +0900
Masami Hiramatsu <> wrote:

> > Perhaps we could enable kprobes at early init?
> It should be possible, I will try to find what blocks it. I guess after we
> switch early_text_poke() to text_poke(), we can use kprobes on x86. But
> for other archs, I need to investigate more.

OK, I just follow the kernel init related to kprobes

 -> trace_init()
 -> rcu_init_nohz()
 -> perf_event_init()
 -> arch_call_rest_init()
   -> rest_init()
     -> rcu_scheduler_starting()
     -> kernel_thread(kernel_init)
 -> kernel_init_freeable()
   -> wait_for_completion(&kthreadd_done);
   -> workqueue_init()
   -> smp_init()
   -> do_basic_setup()
     -> do_initcalls()
       -> do_initcall_level()
         (in subsys-level)
         -> init_kprobes()

Since optprobe uses workqueue, we can not move it before workqueue_init().
(but maybe we can disable it in early stage)
Also, since kprobes depends on rcu, I guess we can not move it before
for kretprobe, we need to get the possible cpus, we need a fix if we move
it before before smp_init().
However, there is no reason we need to run it in subsys level. We can
move init_kprobes() in core or pure level safely.

Thank you,

Masami Hiramatsu <>

  reply	other threads:[~2019-05-22  7:30 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-21  7:56 Masami Hiramatsu
2019-05-21  7:56 ` [PATCH 1/2] kprobes: Initialize kprobes at subsys_initcall Masami Hiramatsu
2019-05-21  7:56 ` [PATCH 2/2] tracing/kprobe: Add kprobe_event= boot parameter Masami Hiramatsu
2019-05-21 13:33 ` [PATCH 0/2] Enable new kprobe event at boot Steven Rostedt
2019-05-21 15:39   ` Masami Hiramatsu
2019-05-22  7:30     ` Masami Hiramatsu [this message]
2019-05-22  8:02       ` Masami Hiramatsu

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