On Sun, Sep 20, 2020 at 11:12:38PM +0200, Krzysztof Kozlowski wrote:
> If interrupt comes late, during probe error path or device remove (could
> be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler
> i2c_imx_isr() will access registers with the clock being disabled. This
> leads to external abort on non-linefetch on Toradex Colibri VF50 module
> (with Vybrid VF5xx):
>
> Unhandled fault: external abort on non-linefetch (0x1008) at 0x8882d003
> Internal error: : 1008 [#1] ARM
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0 #607
> Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
> (i2c_imx_isr) from [<8017009c>] (free_irq+0x25c/0x3b0)
> (free_irq) from [<805844ec>] (release_nodes+0x178/0x284)
> (release_nodes) from [<80580030>] (really_probe+0x10c/0x348)
> (really_probe) from [<80580380>] (driver_probe_device+0x60/0x170)
> (driver_probe_device) from [<80580630>] (device_driver_attach+0x58/0x60)
> (device_driver_attach) from [<805806bc>] (__driver_attach+0x84/0xc0)
> (__driver_attach) from [<8057e228>] (bus_for_each_dev+0x68/0xb4)
> (bus_for_each_dev) from [<8057f3ec>] (bus_add_driver+0x144/0x1ec)
> (bus_add_driver) from [<80581320>] (driver_register+0x78/0x110)
> (driver_register) from [<8010213c>] (do_one_initcall+0xa8/0x2f4)
> (do_one_initcall) from [<80c0100c>] (kernel_init_freeable+0x178/0x1dc)
> (kernel_init_freeable) from [<80807048>] (kernel_init+0x8/0x110)
> (kernel_init) from [<80100114>] (ret_from_fork+0x14/0x20)
>
> Additionally, the i2c_imx_isr() could wake up the wait queue
> (imx_i2c_struct->queue) before its initialization happens.
>
> The resource-managed framework should not be used for interrupt handling,
> because the resource will be released too late - after disabling clocks.
> The interrupt handler is not prepared for such case.
>
> Fixes: 1c4b6c3bcf30 ("i2c: imx: implement bus recovery")
> Cc: <sta...@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <k...@kernel.org>
Acked-by: Oleksij Rempel <o.rem...@pengutronix.de>
Thank you!
> ---
>
> Changes since v2:
> 1. Rebase
>
> Changes since v1:
> 1. Remove the devm- and use regular methods.
> ---
> drivers/i2c/busses/i2c-imx.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 63f4367c312b..c98529c76348 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1169,14 +1169,6 @@ static int i2c_imx_probe(struct platform_device *pdev)
> return ret;
> }
>
> - /* Request IRQ */
> - ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, IRQF_SHARED,
> - pdev->name, i2c_imx);
> - if (ret) {
> - dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> - goto clk_disable;
> - }
> -
> /* Init queue */
> init_waitqueue_head(&i2c_imx->queue);
>
> @@ -1195,6 +1187,14 @@ static int i2c_imx_probe(struct platform_device *pdev)
> if (ret < 0)
> goto rpm_disable;
>
> + /* Request IRQ */
> + ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> + pdev->name, i2c_imx);
> + if (ret) {
> + dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> + goto rpm_disable;
> + }
> +
> /* Set up clock divider */
> i2c_imx->bitrate = I2C_MAX_STANDARD_MODE_FREQ;
> ret = of_property_read_u32(pdev->dev.of_node,
> @@ -1237,13 +1237,12 @@ static int i2c_imx_probe(struct platform_device *pdev)
>
> clk_notifier_unregister:
> clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
> + free_irq(irq, i2c_imx);
> rpm_disable:
> pm_runtime_put_noidle(&pdev->dev);
> pm_runtime_disable(&pdev->dev);
> pm_runtime_set_suspended(&pdev->dev);
> pm_runtime_dont_use_autosuspend(&pdev->dev);
> -
> -clk_disable:
> clk_disable_unprepare(i2c_imx->clk);
> return ret;
> }
> @@ -1251,7 +1250,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
> static int i2c_imx_remove(struct platform_device *pdev)
> {
> struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
> - int ret;
> + int irq, ret;
>
> ret = pm_runtime_get_sync(&pdev->dev);
> if (ret < 0)
> @@ -1271,6 +1270,9 @@ static int i2c_imx_remove(struct platform_device *pdev)
> imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
>
> clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
> + irq = platform_get_irq(pdev, 0);
> + if (irq >= 0)
> + free_irq(irq, i2c_imx);
> clk_disable_unprepare(i2c_imx->clk);
>
> pm_runtime_put_noidle(&pdev->dev);
> --
> 2.17.1
>
>
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>
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