[IA64] fix kmalloc(0) in arch/ia64/pci/pci.c

Hiroyuki Kamezawa reported the problem that pci_acpi_scan_root() of
ia64 might call kmalloc_node() with zero size.

Currently ia64's pci_acpi_scan_root() assumes that _CRS method of root
bridge has at least one resource window. But, the root bridges that
has no resource window must be taken into account.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index 3549f3b4259..73696b4a2ee 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -354,10 +354,13 @@ pci_acpi_scan_root(struct acpi_device *device, int domain, int bus)
 
         acpi_walk_resources(device->handle, METHOD_NAME__CRS, count_window,
                         &windows);
-        controller->window = kmalloc_node(sizeof(*controller->window) * windows,
-                        GFP_KERNEL, controller->node);
-        if (!controller->window)
-                goto out2;
+        if (windows) {
+                controller->window =
+                        kmalloc_node(sizeof(*controller->window) * windows,
+                                     GFP_KERNEL, controller->node);
+                if (!controller->window)
+                        goto out2;
+        }
 
         name = kmalloc(16, GFP_KERNEL);
         if (!name)