diff --git a/gen_syscalls-inl.h b/gen_syscalls-inl.h
index f885081..e631424 100644
--- a/gen_syscalls-inl.h
+++ b/gen_syscalls-inl.h
@@ -92,6 +92,16 @@
 #define __NR_clone3 435
 #endif
 
+#ifndef __NR_userfaultfd
+#ifdef __x86_64__
+#define __NR_userfaultfd 323
+#elif __i386__
+#define __NR_userfaultfd 374
+#elif __arm64__
+#define __NR_userfaultfd 282
+#endif
+#endif /* __NR_userfaultfd */
+
 #ifndef __NR_membarrier
 #ifdef __x86_64__
 #define __NR_membarrier 324