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Date: Tue, 10 Nov 2009 11:40:04 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
       Masami Hiramatsu <mhiramat@redhat.com>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Mike Galbraith <efault@gmx.de>, Paul Mackerras <paulus@samba.org>,
       Steven Rostedt <rostedt@goodmis.org>, Li Zefan <lizf@cn.fujitsu.com>,
       Jason Baron <jbaron@redhat.com>
Subject: Re: [PATCH v2] tracing: Protect the buffer from recursion in perf
Message-ID: <20091110104002.GE5255@nowhere>
References: <4AF24144.30003@redhat.com> <1257477185-7838-1-git-send-email-fweisbec@gmail.com> <1257848862.4648.33.camel@twins>
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On Tue, Nov 10, 2009 at 11:27:42AM +0100, Peter Zijlstra wrote:
> There already is recursion protection in
> kernel/perf_event.c:perf_swevent_recursion_context() and thereabouts.
> Could you not fix this by widening its scope?


Hmm, indeed.
I could probably use perf_swevent_recursion_context() directly from
the tracing fill path. And then split up a bit do_perf_sw_event()
so that it continues to check the recursion for normal software events
but not for trace events (for which we would already explicitly
call perf_swevent_recursion_context()).

I'll try that, thanks!

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