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Date: Fri, 15 Nov 2013 13:28:33 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        Vince Weaver <vincent.weaver@maine.edu>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Dave Jones <davej@redhat.com>
Subject: Re: perf/tracepoint: another fuzzer generated lockup
Message-ID: <20131115122833.GE10456@twins.programming.kicks-ass.net>
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On Fri, Nov 15, 2013 at 10:16:18AM +0900, Masami Hiramatsu wrote:
> Kprobes itself can detect nested call by using per-cpu current-running
> kprobe pointer. And if it is nested, it just skips calling handlers.
> Anyway, I don't recommend to probe inside the handlers, but yes,
> you can trace perf-handler by ftrace B). I actually traced a kprobe-bug
> by kprobe-tracer last night, that was amazing :)

Ah, ok, so that would avoid the worst problems. Good. Should we still
mark the entire perf swevent path as __kprobes just to be sure?