iommu/vt-d: Check for NULL pointer in dmar_acpi_dev_scope_init()
When ir_dev_scope_init() is called via a rootfs initcall it
will check for irq_remapping_enabled before it calls
(indirectly) into dmar_acpi_dev_scope_init() which uses the
dmar_tbl pointer without any checks.
The AMD IOMMU driver also sets the irq_remapping_enabled
flag which causes the dmar_acpi_dev_scope_init() function to
be called on systems with AMD IOMMU hardware too, causing a
boot-time kernel crash.
Signed-off-by: Joerg Roedel <joro@8bytes.org>
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 56e1c79..e531a2b 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -657,7 +657,12 @@
static int __init dmar_acpi_dev_scope_init(void)
{
- struct acpi_dmar_andd *andd = (void *)dmar_tbl + sizeof(struct acpi_table_dmar);
+ struct acpi_dmar_andd *andd;
+
+ if (dmar_tbl == NULL)
+ return -ENODEV;
+
+ andd = (void *)dmar_tbl + sizeof(struct acpi_table_dmar);
while (((unsigned long)andd) <
((unsigned long)dmar_tbl) + dmar_tbl->length) {