diff --git a/sys/kern/sysv_shm.c b/sys/kern/sysv_shm.c
index 6fcfdf23e28a..866a6ce6505c 100644
--- a/sys/kern/sysv_shm.c
+++ b/sys/kern/sysv_shm.c
@@ -249,7 +249,11 @@ shmat(p, uap)
 	if (i >= shminfo.shmseg)
 		return EMFILE;
 	size = round_page(shmseg->shm_segsz);
+#ifdef VM_PROT_READ_IS_EXEC
+	prot = VM_PROT_READ | VM_PROT_EXECUTE;
+#else
 	prot = VM_PROT_READ;
+#endif
 	if ((uap->shmflg & SHM_RDONLY) == 0)
 		prot |= VM_PROT_WRITE;
 	flags = MAP_ANON | MAP_SHARED;