Re: [PATCH v3] ACPI: scan: Avoid registering platform devices with resource overlaps

[Jarkko Sakkinen <jarkko@kernel.org>]

On Fri, Aug 07, 2026 at 12:22:37PM +0200, Rafael J. Wysocki wrote:
> From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> 
> If acpi_dev_get_resources() returns overlapping I/O or memory resources,
> the subsequent registration of a platform device will fail with -EBUSY
> due to a resource conflict.  This is reported to happen on Acer Aspire
> ES1-572 [1].
> 
> Avoid that by adjusting resources returned by acpi_dev_get_resources()
> to eliminate partial overlaps between them.
> 
> This has not been regarded as necessary before because putting
> overlapping resources into the _CRS of one device is really pointless,
> but now that the issue has been reported to actually happen in the
> field, it needs to be done.
> 
> Fixes: ab06eb920401 ("ACPI: scan: Register platform devices for fixed event buttons")
> Reported-by: Julien <julien82453@gmail.com>
> Closes: https://lore.kernel.org/linux-integrity/CAJOGg3z6LJPDsdPNBxajgy8_wQxfhYBRxe4EiurZf3kPU5A5Bw@mail.gmail.com/ [1]
> Cc: All applicable <stable@vger.kernel.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> 
> v2 -> v3:
>    * Use resource_union() and adjust code and comment (Andy)
>    * Include ioport.h directly
> 
> v1 -> v2:
>    * Add the expanded resource instead of and not in addition to the other
>      overlapping one (Sashiko)
> 
> ---
>  drivers/acpi/acpi_platform.c |   39 +++++++++++++++++++++++++++++++++++++--
>  1 file changed, 37 insertions(+), 2 deletions(-)
> 
> --- a/drivers/acpi/acpi_platform.c
> +++ b/drivers/acpi/acpi_platform.c
> @@ -12,6 +12,7 @@
>  #include <linux/bits.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
> +#include <linux/ioport.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/dma-mapping.h>
> @@ -71,6 +72,36 @@ static struct notifier_block acpi_platfo
>  	.notifier_call = acpi_platform_device_remove_notify,
>  };
>  
> +static unsigned int acpi_platform_adjust_resources(struct acpi_device *adev,
> +						   struct resource *new_res,
> +						   struct resource *resources,
> +						   unsigned int count)
> +{
> +	unsigned int i;
> +
> +	if (!(new_res->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
> +		return count;
> +
> +	for (i = 0; i < count; ) {
> +		struct resource *res = &resources[i];
> +
> +		if (resource_type(new_res) != resource_type(res) ||
> +		    !resource_union(new_res, res, new_res)) {
> +			i++;
> +			continue;
> +		}
> +
> +		dev_info(&adev->dev, "%pR expanded to avoid overlap\n", new_res);
> +		/*
> +		 * Eliminate the previously processed resource that overlapped
> +		 * with the new one because it is not necessary any more.
> +		 */
> +		memmove(res, res + 1, (--count - i) * sizeof(*res));
> +	}
> +
> +	return count;
> +}
> +
>  static void acpi_platform_fill_resource(struct acpi_device *adev,
>  	const struct resource *src, struct resource *dest)
>  {
> @@ -151,10 +182,14 @@ struct platform_device *acpi_create_plat
>  				return ERR_PTR(-ENOMEM);
>  			}
>  			count = 0;
> -			list_for_each_entry(rentry, &resource_list, node)
> +			list_for_each_entry(rentry, &resource_list, node) {
> +				count = acpi_platform_adjust_resources(adev,
> +								       rentry->res,
> +								       resources,
> +								       count);
>  				acpi_platform_fill_resource(adev, rentry->res,
>  							    &resources[count++]);
> -
> +			}
>  			acpi_dev_free_resource_list(&resource_list);
>  		}
>  	}
> 
> 
> 

Applied to my tree I'll just run some tests.

BR, Jarkko