diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index edc5f002e055..7771b2dd5978 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -1466,5 +1466,7 @@ int __init dmar_ir_support(void)
 {
 	struct acpi_table_dmar *dmar;
 	dmar = (struct acpi_table_dmar *)dmar_tbl;
+	if (!dmar)
+		return 0;
 	return dmar->flags & 0x1;
 }