intel-iommu: Fix oops in device_to_iommu() when devices not found.

(cherry picked from commit 4958c5dc7bcb2e42d985cd26aeafd8a7eca9ab1e)

It's possible for a device in the drhd->devices[] array to be NULL if
it wasn't found at boot time, which means we have to check for that
case.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index efc7c12c805ae4e97b70c8e87886ecee3d6ebfa5..7e4f9e661f06c62346fc97438716503ac42a5bd2 100644 (file)
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -452,7 +452,8 @@ static struct intel_iommu *device_to_iommu(u8 bus, u8 devfn)
                            drhd->devices[i]->bus->number == bus &&
                            drhd->devices[i]->devfn == devfn)
                                return drhd->iommu;
-                       if (drhd->devices[i]->subordinate &&
+                       if (drhd->devices[i] &&
+                           drhd->devices[i]->subordinate &&
                            drhd->devices[i]->subordinate->number <= bus &&
                            drhd->devices[i]->subordinate->subordinate >= bus)
                                return drhd->iommu;