[Resend][PATCH] Prevent oops at boot with VT-d

[Dirk Hohndel <hohndel@infradead.org>]

This wasn't included in 2.6.29-rc1

With some broken BIOSs when VT-d is enabled, the data structures are
filled incorrectly. This can cause a NULL pointer dereference in very
early boot. 


Signed-off-by: Dirk Hohndel <hohndel@linux.intel.com>
Acked-by: Yu Zhao <yu.zhao@intel.com>
---
 drivers/pci/intel-iommu.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 235fb7a..3dfecb2 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -438,7 +438,8 @@ static struct intel_iommu *device_to_iommu(u8 bus, u8 devfn)
                        continue;
 
                for (i = 0; i < drhd->devices_cnt; i++)
-                       if (drhd->devices[i]->bus->number == bus &&
+                       if (drhd->devices[i] &&
+                           drhd->devices[i]->bus->number == bus &&
                            drhd->devices[i]->devfn == devfn)
                                return drhd->iommu;
 
-- 
1.6.0.6
-- 
Dirk Hohndel
Intel Open Source Technology Center