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

On Fri, Aug 7, 2026 at 2:57 PM Paul Menzel <[email protected]> wrote:
>
> Dear Rafael,
>
>
> Thank you for the patch.
>
> Am 07.08.26 um 12:22 schrieb Rafael J. Wysocki:
> > From: "Rafael J. Wysocki" <[email protected]>
> >
> > 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].
>
> Reading the diff, it might be useful to paste the log warning already here:
>
>      tpm_crb_acpi MSFT0101:00: [Firmware Bug]: Bad ACPI memory layout

It's there in the message pointed to by the Closes: tag though.

> > 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 <[email protected]>
> > Closes: https://lore.kernel.org/linux-integrity/CAJOGg3z6LJPDsdPNBxajgy8_wQxfhYBRxe4EiurZf3kPU5A5Bw@mail.gmail.com/ [1]
> > Cc: All applicable <[email protected]>
> > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > ---
> >
> > 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);
>
> Maybe more normal user understandable:
>
>      %pR expanded to fit all resources to avoid overlap

What about "expanded due to overlap"?  I'd prefer it to be shorter
because the resource printout takes up some message space already.

> For the record, Julian reported that now the lines below are logged:
>
>      MSFT0101:00: [mem 0xfed40000-0xfed4103f] expanded to avoid overlap
>      tpm_crb_acpi MSFT0101:00: [Firmware Bug]: Bad ACPI memory layout

Right, and the second one comes from the driver binding to the device.

> > +             /*
> > +              * 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);
> >               }
> >       }
>
> Reviewed-by: Paul Menzel <[email protected]>

Thank you!