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Date: Thu, 15 Mar 2018 09:31:25 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        syzbot <syzbot+9c0d616860575a73166a@syzkaller.appspotmail.com>,
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        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>
Subject: Re: WARNING in tracepoint_probe_register_prio (2)
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On Wed, Mar 14, 2018 at 05:37:46PM -0400, Steven Rostedt wrote:
> On Tue, 13 Mar 2018 11:29:51 -0400 (EDT)
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
> 
> > Here is a WARN_ON() splat in tracepoint.c, which I suspect is caused
> > by perf trying to register the same probe twice to the tracepoint API.
> > We got another splat on unregister too, which I will forward in a
> > separate email.
> > 
> > Thoughts ?
> 
> Yes, it looks like it's perf not accounting for registered events
> properly.
> 
> Peter?

I've not yet managed to reproduce, but if you look at the provided
repro.c file, you'll see it opens two _different_ events.