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Message-ID: <2039525.IqjUGZ56ra@vostro.rjw.lan>
Date: Mon, 02 Sep 2013 14:25:22 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: linux-acpi@...r.kernel.org,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Imre Kaloz <kaloz@...nwrt.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ACPI / LPSS: don't crash if a device has no MMIO resources
On Monday, September 02, 2013 01:30:25 PM Mika Westerberg wrote:
> Intel LPSS devices that are enumerated from ACPI have both MMIO and IRQ
> resources returned in their _CRS method. However, Apple Macbook Air with
> Haswell has LPSS devices enumerated from PCI bus instead and _CRS method
> returns only an interrupt number (but the device has _HID set that causes
> the scan handler to match it).
>
> The current ACPI / LPSS code sets pdata->dev_desc only when MMIO resource
> is found for the device and in case of Macbook Air it is never found. That
> leads to a NULL pointer dereference in register_device_clock().
>
> Correct this by always setting the pdata->dev_desc.
>
> Reported-and-tested-by: Imre Kaloz <kaloz@...nwrt.org>
> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Cc: stable@...r.kernel.org # 3.10+
Queued up for 3.12, thanks for taking care of this Mika!
> ---
> drivers/acpi/acpi_lpss.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index 6a38218..fb78bb9 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -257,12 +257,13 @@ static int acpi_lpss_create_device(struct acpi_device *adev,
> pdata->mmio_size = resource_size(&rentry->res);
> pdata->mmio_base = ioremap(rentry->res.start,
> pdata->mmio_size);
> - pdata->dev_desc = dev_desc;
> break;
> }
>
> acpi_dev_free_resource_list(&resource_list);
>
> + pdata->dev_desc = dev_desc;
> +
> if (dev_desc->clk_required) {
> ret = register_device_clock(adev, pdata);
> if (ret) {
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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