Am Dienstag, den 19.09.2017, 08:23 +0200 schrieb Martin Kaiser:
> When fsl-imx25-tsadc is compiled as a module, loading, unloading and
> reloading the module will lead to a crash.
>
> Unable to handle kernel paging request at virtual address bf005430
> [<c004df6c>] (irq_find_matching_fwspec)
> from [<c028d5ec>] (of_irq_get+0x58/0x74)
> [<c028d594>] (of_irq_get)
> from [<c01ff970>] (platform_get_irq+0x48/0xc8)
> [<c01ff928>] (platform_get_irq)
> from [<bf00e33c>] (mx25_tsadc_probe+0x220/0x2f4 [fsl_imx25_tsadc])
>
> irq_find_matching_fwspec() loops over all registered irq domains. The
> irq domain is still registered from last time the module was loaded but
> the pointer to its operations is invalid after the module was unloaded.
>
> Add a removal function which clears the irq handler and removes the irq
> domain. With this cleanup in place, it's possible to unload and reload
> the module.
>
> Signed-off-by: Martin Kaiser <mar...@kaiser.cx>
> ---
> changes in v2:
> add more details about the crash to the commit message
>
> drivers/mfd/fsl-imx25-tsadc.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/mfd/fsl-imx25-tsadc.c b/drivers/mfd/fsl-imx25-tsadc.c
> index 14189ef..a6423bd 100644
> --- a/drivers/mfd/fsl-imx25-tsadc.c
> +++ b/drivers/mfd/fsl-imx25-tsadc.c
> @@ -179,6 +179,19 @@ static int mx25_tsadc_probe(struct platform_device *pdev)
> return devm_of_platform_populate(dev);
> }
>
> +static int __exit mx25_tsadc_remove(struct platform_device *pdev)
I don't think the __exit annotation makes sense. You can also unbind the
device by using sysfs, in which case you want to do the same IRQ
cleanup.
> +{
> + struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
> + int irq = platform_get_irq(pdev, 0);
> +
> + if (irq) {
> + irq_set_chained_handler_and_data(irq, NULL, NULL);
> + irq_domain_remove(tsadc->domain);
> + }
> +
> + return 0;
> +}
> +
> static const struct of_device_id mx25_tsadc_ids[] = {
> { .compatible = "fsl,imx25-tsadc" },
> { /* Sentinel */ }
> @@ -191,6 +204,7 @@ static struct platform_driver mx25_tsadc_driver = {
> .of_match_table = of_match_ptr(mx25_tsadc_ids),
> },
> .probe = mx25_tsadc_probe,
> + .remove = __exit_p(mx25_tsadc_remove),
> };
> module_platform_driver(mx25_tsadc_driver);
>
