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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>,
	peterz@infradead.org, mathieu.desnoyers@efficios.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] tracing: kprobes: Prohibit probing on notrace functions
Date: Thu, 26 Jul 2018 09:41:06 +0900	[thread overview]
Message-ID: <20180726094106.1e8db6e2df788de20e696566@kernel.org> (raw)
In-Reply-To: <20180713081803.1b78ebbc@gandalf.local.home>

On Fri, 13 Jul 2018 08:18:03 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Fri, 13 Jul 2018 11:53:01 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > On Thu, 12 Jul 2018 13:54:12 -0400
> > Francis Deslauriers <francis.deslauriers@efficios.com> wrote:
> > 
> > > From: Masami Hiramatsu <mhiramat@kernel.org>
> > > 
> > > Prohibit kprobe-events probing on notrace function.
> > > Since probing on the notrace function can cause recursive
> > > event call. In most case those are just skipped, but
> > > in some case it falls into infinite recursive call.  
> > 
> > BTW, I'm considering to add an option to allow putting
> > kprobes on notrace function - just for debugging 
> > ftrace by kprobes. That is "developer only" option
> > so generally it should be disabled, but for debugging
> > the ftrace, we still need it. Or should I introduce
> > another kprobes module for debugging it?
> 
> No, I think the former is better (to add an option to allow putting
> kprobes on notrace functions). By default we let people protect
> themselves. But if then provide a switch that lets you do things that
> might let you shoot yourself in the foot.

I'm adding CONFIG_KPROBE_EVENTS_ON_NOTRACE kconfig which allows
kprobes on notrace function. I think we don't need to make it
online switchable, since it is only good for ftrace developers.

Thank you,

> 
> BTW, I'm now leaving on vacation. I'll be back on the 23rd and will be
> looking for patches that I should be pulling in then.
> 
> Thanks!
> 
> -- Steve


-- 
Masami Hiramatsu <mhiramat@kernel.org>

  reply	other threads:[~2018-07-26  0:41 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-14 14:58 [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist Francis Deslauriers
2017-07-14 14:58 ` [PATCH 1/2] kprobe: fix: Add _ASM_NOKPROBE to x86 apic interrupt macro Francis Deslauriers
2017-07-14 14:58 ` [PATCH 2/2] kprobe: fix: Add ftrace_ops_assist_func to kprobe blacklist Francis Deslauriers
2017-07-14 18:29   ` Steven Rostedt
2018-03-16 15:18     ` Francis Deslauriers
2018-03-16 15:25       ` Steven Rostedt
2018-03-16 16:28         ` Mathieu Desnoyers
2018-03-16 16:41           ` Steven Rostedt
2018-03-16 16:48             ` Steven Rostedt
2018-03-16 17:53               ` Mathieu Desnoyers
2018-03-16 19:02                 ` Steven Rostedt
2018-03-17  0:13                 ` Masami Hiramatsu
2018-03-17  1:22                   ` Masami Hiramatsu
2018-03-17  3:01                     ` Steven Rostedt
2018-03-17  7:57                       ` Masami Hiramatsu
2018-07-03 22:30                     ` Steven Rostedt
2018-07-11 19:34                       ` Francis Deslauriers
2018-07-11 19:56                         ` Steven Rostedt
2018-07-12  0:40                           ` Francis Deslauriers
2018-07-12 13:59                             ` Masami Hiramatsu
2018-07-12 13:46                         ` Masami Hiramatsu
2018-03-17  0:08           ` Masami Hiramatsu
2018-07-12 17:54   ` [PATCH 0/2] tracing: kprobes: Prohibit probing on notrace functions Francis Deslauriers
2018-07-12 17:54     ` [PATCH 1/2] " Francis Deslauriers
2018-07-12 21:49       ` Steven Rostedt
2018-07-13  2:53       ` Masami Hiramatsu
2018-07-13 12:18         ` Steven Rostedt
2018-07-26  0:41           ` Masami Hiramatsu [this message]
2018-07-26  1:13             ` Steven Rostedt
2018-07-12 17:54     ` [PATCH 2/2] selftest/ftrace: Move kprobe selftest function to separate compile unit Francis Deslauriers
2017-07-14 18:27 ` [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist Steven Rostedt
2017-07-16 15:59   ` Masami Hiramatsu
2017-07-16 14:37 ` Masami Hiramatsu
2017-07-16 15:46   ` Masami Hiramatsu
2017-07-17 18:46     ` Francis Deslauriers

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