diff --git a/ipc/shm.c b/ipc/shm.c
index dda8f1f..9e51bf2 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -493,7 +493,8 @@
 	if (size < SHMMIN || size > ns->shm_ctlmax)
 		return -EINVAL;
 
-	if (ns->shm_tot + numpages > ns->shm_ctlall)
+	if (ns->shm_tot + numpages < ns->shm_tot ||
+			ns->shm_tot + numpages > ns->shm_ctlall)
 		return -ENOSPC;
 
 	shp = ipc_rcu_alloc(sizeof(*shp));