Commit 44cd613c authored Dec 02, 2009 by David Woodhouse

intel-iommu: Fix oops with intel_iommu=igfx_off



The hotplug notifier will call find_domain() to see if the device in
question has been assigned an IOMMU domain. However, this should never
be called for devices with a "dummy" domain, such as graphics devices
when intel_iommu=igfx_off is set and the corresponding IOMMU isn't even
initialised. If you do that, it'll oops as it dereferences the (-1)
pointer.

The notifier function should check iommu_no_mapping() for the
device before doing anything else.

Cc: stable@kernel.org
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

parent 5595b528

drivers/pci/intel-iommu.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -3247,6 +3247,9 @@ static int device_notifier(struct notifier_block *nb,
		struct pci_dev *pdev = to_pci_dev(dev);
		struct dmar_domain *domain;

		if (iommu_no_mapping(dev))
		return 0;

		domain = find_domain(pdev);
		if (!domain)
		return 0;