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Subject: Re: [PATCH 1/3] clocksource/arm_arch_timer: mark arch_counter_get_*
 as notrace
To:     Anders Roxell <anders.roxell@linaro.org>, mark.rutland@arm.com,
        daniel.lezcano@linaro.org, tglx@linutronix.de
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        mingo@redhat.com
References: <20190603091256.25012-1-anders.roxell@linaro.org>
From:   Marc Zyngier <marc.zyngier@arm.com>
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Organization: ARM Ltd
Message-ID: <c9197fdd-6b3b-d92b-055a-756ba3da44c2@arm.com>
Date:   Mon, 3 Jun 2019 10:23:30 +0100
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In-Reply-To: <20190603091256.25012-1-anders.roxell@linaro.org>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Anders,


On 03/06/2019 10:12, Anders Roxell wrote:
> When CONFIG_FUNCTION_GRAPH_TRACER is enabled we end up in this circular
> call trace since function arch_counter_get_cntvct() isn't marked with no
> trace:
> 
> [   17.914934] Call trace:
> [   17.915211]  ftrace_return_to_handler+0x194/0x288
> [   17.915551]  return_to_handler+0x1c/0x38
> [   17.915855]  trace_clock_local+0x38/0x88
> [   17.916159]  function_graph_enter+0xf0/0x258
> [   17.916465]  prepare_ftrace_return+0x60/0x90
> [   17.916772]  ftrace_graph_caller+0x1c/0x24
> [   17.917093]  arch_counter_get_cntvct+0x10/0x30
> [   17.917417]  sched_clock+0x70/0x218
> [   17.917723]  trace_clock_local+0x38/0x88
> [   17.918026]  function_graph_enter+0xf0/0x258
> [   17.918332]  prepare_ftrace_return+0x60/0x90
> [   17.918649]  ftrace_graph_caller+0x1c/0x24
> [   17.918963]  arch_counter_get_cntvct+0x10/0x30
> [   17.919286]  sched_clock+0x70/0x218
> 
> Rework so that function arch_counter_get_cntvct() is marked with notrace.
> 
> Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters")
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>

This has already been queued by Daniel, I believe [1].

[1] https://lore.kernel.org/lkml/1558689025-50679-1-git-send-email-julien.thierry@arm.com/

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...