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Date: Mon, 15 Jul 2013 20:20:12 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Frederic Weisbecker <fweisbec@gmail.com>, linux-kernel@vger.kernel.org,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Andrew Morton <akpm@linux-foundation.org>, jovi.zhangwei@huawei.com,
        Jiri Olsa <jolsa@redhat.com>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH V2] tracing/kprobe: Wait for disabling all running
	kprobe handlers
Message-ID: <20130715182012.GB18505@redhat.com>
References: <20130709082149.GK25631@dyad.programming.kicks-ass.net> <20130709093526.20138.93100.stgit@mhiramat-M0-7522>
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On 07/09, Masami Hiramatsu wrote:
>
> Wait for disabling all running kprobe handlers when a kprobe
> event is disabled, since the caller, trace_remove_event_call()
> supposes that a removing event is disabled completely by
> disabling the event.
> With this change, ftrace can ensure that there is no running
> event handlers after disabling it.
>
> Changes in V2:
>  - Comment (in code) for clarify why we need to wait there.
>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Agreed.

We need this change in any case, whatever we do in trace/trace_events.c
and in unregister_trace_probe().

Oleg.