diff --git a/libc/kernel/uapi/linux/prctl.h b/libc/kernel/uapi/linux/prctl.h
index 6e3426c..c8118da 100644
--- a/libc/kernel/uapi/linux/prctl.h
+++ b/libc/kernel/uapi/linux/prctl.h
@@ -153,6 +153,8 @@
 #define PR_SET_TAGGED_ADDR_CTRL 55
 #define PR_GET_TAGGED_ADDR_CTRL 56
 #define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+#define PR_SET_IO_FLUSHER 57
+#define PR_GET_IO_FLUSHER 58
 #define PR_SET_VMA 0x53564d41
 #define PR_SET_VMA_ANON_NAME 0
 #endif