From: Dirk Hohndel <hohndel@linux.intel.com>
Date: Sun, 11 Jan 2009 15:33:51 +0000 (+0000)
Subject: Prevent oops at boot with VT-d
X-Git-Tag: firefly_0821_release~15878
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=288e4877f94a3b144aadc206e7796921d02432c1;p=firefly-linux-kernel-4.4.55.git

Prevent oops at boot with VT-d

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>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 235fb7a5a8a5..3dfecb20d5e7 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;