linux-kernel - Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths

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Date:   Mon, 15 Jun 2020 10:17:07 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Krzysztof Kozlowski <krzk@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vladimir Oltean <vladimir.oltean@....com>,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Wolfram Sang <wsa@...nel.org>, stable@...r.kernel.org,
        kernel@...gutronix.de
Subject: Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt
 in exit paths

On 6/15/20 10:07 AM, Krzysztof Kozlowski wrote:
> If interrupt comes late, during probe error path or device remove (could
> be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler
> dspi_interrupt() will access registers with the clock being disabled.  This
> leads to external abort on non-linefetch on Toradex Colibri VF50 module
> (with Vybrid VF5xx):
> 
>     $ echo 4002d000.spi > /sys/devices/platform/soc/40000000.bus/4002d000.spi/driver/unbind
> 
>     Unhandled fault: external abort on non-linefetch (0x1008) at 0x8887f02c
>     Internal error: : 1008 [#1] ARM
>     CPU: 0 PID: 136 Comm: sh Not tainted 5.7.0-next-20200610-00009-g5c913fa0f9c5-dirty #74
>     Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
>       (regmap_mmio_read32le) from [<8061885c>] (regmap_mmio_read+0x48/0x68)
>       (regmap_mmio_read) from [<8060e3b8>] (_regmap_bus_reg_read+0x24/0x28)
>       (_regmap_bus_reg_read) from [<80611c50>] (_regmap_read+0x70/0x1c0)
>       (_regmap_read) from [<80611dec>] (regmap_read+0x4c/0x6c)
>       (regmap_read) from [<80678ca0>] (dspi_interrupt+0x3c/0xa8)
>       (dspi_interrupt) from [<8017acec>] (free_irq+0x26c/0x3cc)
>       (free_irq) from [<8017dcec>] (devm_irq_release+0x1c/0x20)
>       (devm_irq_release) from [<805f98ec>] (release_nodes+0x1e4/0x298)
>       (release_nodes) from [<805f9ac8>] (devres_release_all+0x40/0x60)
>       (devres_release_all) from [<805f5134>] (device_release_driver_internal+0x108/0x1ac)
>       (device_release_driver_internal) from [<805f521c>] (device_driver_detach+0x20/0x24)
> 
> Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> 
> ---
> 
> This is an follow up of my other patch for I2C IMX driver [1]. Let's fix the
> issues consistently.
> 
> [1] https://lore.kernel.org/lkml/1592130544-19759-2-git-send-email-krzk@kernel.org/T/#u
> 
> Changes since v1:
> 1. Disable the IRQ instead of using non-devm interface.
> ---
>  drivers/spi/spi-fsl-dspi.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index 58190c94561f..023e05c53b85 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -1400,7 +1400,7 @@ static int dspi_probe(struct platform_device *pdev)
>  		ret = dspi_request_dma(dspi, res->start);
>  		if (ret < 0) {
>  			dev_err(&pdev->dev, "can't get dma channels\n");
> -			goto out_clk_put;
> +			goto disable_irq;
>  		}
>  	}
>  
> @@ -1415,11 +1415,14 @@ static int dspi_probe(struct platform_device *pdev)
>  	ret = spi_register_controller(ctlr);
>  	if (ret != 0) {
>  		dev_err(&pdev->dev, "Problem registering DSPI ctlr\n");
> -		goto out_clk_put;
> +		goto disable_irq;
>  	}
>  
>  	return ret;
>  
> +disable_irq:
> +	if (dspi->irq > 0)
> +		disable_irq(dspi->irq);
>  out_clk_put:
>  	clk_disable_unprepare(dspi->clk);
>  out_ctlr_put:
> @@ -1435,6 +1438,8 @@ static int dspi_remove(struct platform_device *pdev)
>  
>  	/* Disconnect from the SPI framework */
>  	dspi_release_dma(dspi);
> +	if (dspi->irq > 0)
> +		disable_irq(dspi->irq);

What happens, if you re-bind the driver?
Is the IRQ still working?
Who is taking care of calling the enable_irq() again?
What happens, if you really have a shared IRQ line?
Is the IRQ disabled for all other devices on the same IRQ line?

>  	clk_disable_unprepare(dspi->clk);
>  	spi_unregister_controller(dspi->ctlr);
>  
> 
Marc

-- 
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