amd_iommu: do not dereference a NULL pointer address.

under low memory conditions, alloc_pte() may return a NULL pointer. iommu_map_page() does not check it and will panic the system. Signed-off-by: Maurizio Lombardi <[email protected]> Signed-off-by: Joerg Roedel <[email protected]>
sum-it · Sep 25, 2014 · 63eaa75 · 63eaa75
1 parent cafd254
commit 63eaa75
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
@@ -1393,6 +1393,9 @@ static int iommu_map_page(struct protection_domain *dom,
 	count     = PAGE_SIZE_PTE_COUNT(page_size);
 	pte       = alloc_pte(dom, bus_addr, page_size, NULL, GFP_KERNEL);
 
+	if (!pte)
+		return -ENOMEM;
+
 	for (i = 0; i < count; ++i)
 		if (IOMMU_PTE_PRESENT(pte[i]))
 			return -EBUSY;