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Subject: Re: [RFC PATCH V2] tracing/kprobe: Wait for disabling all running
 kprobe handlers
From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Oleg Nesterov <oleg@redhat.com>, 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>
Date: Thu, 18 Jul 2013 10:35:53 -0400
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	 <20130715182012.GB18505@redhat.com> <51E7DA79.4060505@hitachi.com>
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On Thu, 2013-07-18 at 21:07 +0900, Masami Hiramatsu wrote:
> (2013/07/16 3:20), Oleg Nesterov wrote:
> > 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().
> 
> Steven, I think this patch is still needed anyway even if we are
> discussing file handling bugs, because this fixes another timing bug.

Sure, I'll pull that into my queue now.

-- Steve


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