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From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>,
	Julien Thierry <julien.thierry@arm.com>,
	linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] clocksource/arm_arch_timer: Don't trace count reader functions
Date: Fri, 24 May 2019 12:42:39 +0200	[thread overview]
Message-ID: <a1af63f8-1b3e-a959-d309-7360679739a2@linaro.org> (raw)
In-Reply-To: <9adf92c2-b7a5-00a3-ff09-58484d9bb9db@arm.com>

On 24/05/2019 11:53, Marc Zyngier wrote:
> On 24/05/2019 10:10, Julien Thierry wrote:
>> With v5.2-rc1, The ftrace functions_graph tracer locks up whenever it is
>> enabled on arm64.
>>
>> Since commit 0ea415390cd3 ("clocksource/arm_arch_timer: Use
>> arch_timer_read_counter to access stable counters") a function pointer
>> is consistently used to read the counter instead of potentially
>> referencing an inlinable function.
>>
>> The graph tacers relies on accessing the timer counters to compute the
> 
> nit: tracers
> 
>> time spent in functions which causes the lockup when attempting to trace
>> these code paths.
>>
>> Annontate the arm arch timer counter accessors as notrace.
> 
> nit: Annotate
> 
>>
>> Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use
>>        arch_timer_read_counter to access stable counters")
>> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
>> Cc: Marc Zyngier <marc.zyngier@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Steven Rostedt <rostedt@goodmis.org>
>> ---

[ ... ]

> Well spotted, thanks Julien.
> 
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> Daniel, can you please pick this up for the next batch of clocksource fixes?

Sure.

I will take care of fixing the comments, no need to resend.

Thanks

  -- Daniel


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  reply	other threads:[~2019-05-24 10:42 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-24  9:10 Julien Thierry
2019-05-24  9:53 ` Marc Zyngier
2019-05-24 10:42   ` Daniel Lezcano [this message]
2019-05-24 13:36 ` Steven Rostedt

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