Message-ID: <55472A80.9020904@linaro.org>
Date: Mon, 04 May 2015 10:14:56 +0200
From: Daniel Lezcano <daniel.lezcano@linaro.org>
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To: Yingjoe Chen <yingjoe.chen@mediatek.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>, Arnd Bergmann <arnd@arndb.de>,
        Olof Johansson <olof@lixom.net>
CC: Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Russell King <linux@arm.linux.org.uk>,
        Jason Cooper <jason@lakedaemon.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Marc Carino <marc.ceeeee@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com,
        Sascha Hauer <kernel@pengutronix.de>
Subject: Re: [PATCH 1/7] clocksource: mediatek: Don't run event_handler if
 it is NULL
References: <1430466210-22963-1-git-send-email-yingjoe.chen@mediatek.com> <1430466210-22963-2-git-send-email-yingjoe.chen@mediatek.com>
In-Reply-To: <1430466210-22963-2-git-send-email-yingjoe.chen@mediatek.com>
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On 05/01/2015 09:43 AM, Yingjoe Chen wrote:
> Spurious timer interrupt is noticed in mtk timer and cause kernel
> crash. In mtk_timer_interrupt(), only run event_handler if it is
> not NULL.
>
> Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
> ---
>   drivers/clocksource/mtk_timer.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
> index 68ab423..85e0ab5 100644
> --- a/drivers/clocksource/mtk_timer.c
> +++ b/drivers/clocksource/mtk_timer.c
> @@ -143,7 +143,8 @@ static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
>
>   	/* Acknowledge timer0 irq */
>   	writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
> -	evt->dev.event_handler(&evt->dev);
> +	if (evt->dev.event_handler)
> +		evt->dev.event_handler(&evt->dev);
>
>   	return IRQ_HANDLED;
>   }
>

This fix does not look good.

Could you try by requesting the irq *after* 
clockevents_config_and_register in the init sequence [1] ?

Thanks
   -- Daniel

[1] 
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1096be084ac59927158ce80ff1d31c33eed0e565

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