diff --git a/libc/kernel/uapi/linux/userfaultfd.h b/libc/kernel/uapi/linux/userfaultfd.h
index 46d7472..0f18ecc 100644
--- a/libc/kernel/uapi/linux/userfaultfd.h
+++ b/libc/kernel/uapi/linux/userfaultfd.h
@@ -73,7 +73,7 @@
       __u64 reserved3;
     } reserved;
   } arg;
-} __packed;
+} __attribute__((__packed__));
 #define UFFD_EVENT_PAGEFAULT 0x12
 #define UFFD_EVENT_FORK 0x13
 #define UFFD_EVENT_REMAP 0x14