--- 84a524afb3dcdffdd60c7ef1eaf2672acd7731ca
+++ 9d12ed56bfbc6116db691245a311ae313bce2e2e
@@ -138,7 +138,7 @@ struct vm_area_struct {
 					   within vm_mm. */
 
 	/* linked list of VM areas per task, sorted by address */
-	struct vm_area_struct *vm_next;
+	struct vm_area_struct *vm_next, *vm_prev;
 
 	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
 	unsigned long vm_flags;		/* Flags, see mm.h. */