diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 6bcb045d2bd2f8ab3b1234e13f00be719dc0441e..9b436c21195ec6b16465bb6e1964e2ad343b8321 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -64,6 +64,11 @@ static unsigned long mmap_rnd(void)
 	return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
 }
 
+static unsigned long mmap_base_legacy(void)
+{
+	return TASK_UNMAPPED_BASE + mmap_rnd();
+}
+
 static inline unsigned long mmap_base(void)
 {
 	unsigned long gap = rlimit(RLIMIT_STACK);
@@ -89,7 +94,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	 * bit is set, or if the expected stack growth is unlimited:
 	 */
 	if (mmap_is_legacy()) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
+		mm->mmap_base = mmap_base_legacy();
 		mm->get_unmapped_area = arch_get_unmapped_area;
 	} else {
 		mm->mmap_base = mmap_base();
@@ -164,7 +169,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	 * bit is set, or if the expected stack growth is unlimited:
 	 */
 	if (mmap_is_legacy()) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
+		mm->mmap_base = mmap_base_legacy();
 		mm->get_unmapped_area = s390_get_unmapped_area;
 	} else {
 		mm->mmap_base = mmap_base();