From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>,
mhiramat@kernel.org, peterz@infradead.org,
mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist
Date: Mon, 17 Jul 2017 00:59:35 +0900 [thread overview]
Message-ID: <20170717005935.dcdf6840d221a265c85f01e4@kernel.org> (raw)
In-Reply-To: <20170714142756.7f7f1745@gandalf.local.home>
On Fri, 14 Jul 2017 14:27:56 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 14 Jul 2017 10:58:33 -0400
> Francis Deslauriers <francis.deslauriers@efficios.com> wrote:
>
>
> > Kretprobe on ftrace_ops_assist_func and another function:
> > Those crashes are triggered when hooking a kretprobe on the
> > ftrace_ops_assist_func symbol and some other functions to make the this first
> > function reacheable. From my understanding, ftrace_ops_assist_func is the
> > function called directly when the kprobe is hit. Thus it should be marked
> > with NOKPROBE_SYMBOL.
> >
>
> Hmm, I'm wondering if I should just make an ftrace section, and black
> list the entire thing. Also that section could be used to not allow
> ftrace to use it either. I've been wanting to start letting ftrace
> trace the tracing code, and perf for that matter. It would be nice to
> be able to debug things like that.
Tracer usually has 2 parts, one is off-line setting part (kicked by
user) and another is core online tracing part (which kicked from
anywhere). Former can be traced but latter is not.
Yeah, I did same thing when I introduced NOKPROBE_SYMBOL() macro.
And I also think that is good for kgdb.
> I would like to also make sections that can be enabled or disabled in
> groups. To group things like the tracing facility and perf and have
> them by default not be traced, but then set a flag that says "sure go
> ahead and trace them". This shouldn't be too hard to do.
We have to notice that is a trigger which allows to shoot yourself
in the foot :)
Thanks,
>
> Hmm, I'll add this as another topic to have for the Linux Plumbers
> tracing track, as well as the kernel tracing topic.
>
> -- Steve
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2017-07-16 15:59 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
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 [this message]
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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