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

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>

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index fd7472f286742b729441f9d1e08223beed6a8200..dcda5212f3bb9b2540ff04bc6b8ef8e1a8e4f0f5 100644 (file)
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -485,7 +485,8 @@ static struct intel_iommu *device_to_iommu(int segment, 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;