ACPI: ioapic: Clear on-stack resource before using it

commit e3d5092b6756b9e0b08f94bbeafcc7afe19f0996 upstream.

The on-stack resource-window 'win' in setup_res() is not
properly initialized. This causes the pointers in the
embedded 'struct resource' to contain stale addresses.

These pointers (in my case the ->child pointer) later get
propagated to the global iomem_resources list, causing a #GP
exception when the list is traversed in
iomem_map_sanity_check().

Fixes: c183619b63ec (x86/irq, ACPI: Implement ACPI driver to support IOAPIC hotplug)
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c
index 6d7ce6e..5e18ccf 100644 (file)
--- a/drivers/acpi/ioapic.c
+++ b/drivers/acpi/ioapic.c
@@ -45,6 +45,12 @@ static acpi_status setup_res(struct acpi_resource *acpi_res, void *data)
        struct resource *res = data;
        struct resource_win win;
 
+       /*
+        * We might assign this to 'res' later, make sure all pointers are
+        * cleared before the resource is added to the global list
+        */
+       memset(&win, 0, sizeof(win));
+
        res->flags = 0;
        if (acpi_dev_filter_resource_type(acpi_res, IORESOURCE_MEM))
                return AE_OK;