diff --git a/libc/kernel/uapi/linux/mman.h b/libc/kernel/uapi/linux/mman.h
index cf1e978..f50b51c 100644
--- a/libc/kernel/uapi/linux/mman.h
+++ b/libc/kernel/uapi/linux/mman.h
@@ -18,6 +18,7 @@
 #define MAP_SHARED 0x01
 #define MAP_PRIVATE 0x02
 #define MAP_SHARED_VALIDATE 0x03
+#define MAP_DROPPABLE 0x08
 #define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
 #define MAP_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
 #define MAP_HUGE_16KB HUGETLB_FLAG_ENCODE_16KB