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Date: Thu, 22 Sep 2016 15:58:03 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Jisheng Zhang <jszhang@marvell.com>
cc: daniel.lezcano@linaro.org, LKML <linux-kernel@vger.kernel.org>,
        LAK <linux-arm-kernel@lists.infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] clocksource/drivers/ti-32k: Prevent ftrace recursion
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On Thu, 22 Sep 2016, Jisheng Zhang wrote:

> Currently ti-32k can be used as a scheduler clock. We properly marked
> omap_32k_read_sched_clock() as notrace but we then call another
> function ti_32k_read_cycles() that _wasn't_ notrace.
> 
> Having a traceable function in the sched_clock() path leads to a
> recursion within ftrace and a kernel crash.

Kernel crash? Doesn't ftrace core prevent recursion?
 
Thanks,

	tglx