diff --git a/arch/um/os-Linux/sys-i386/registers.c b/arch/um/os-Linux/sys-i386/registers.c
index c6183e7aec3d..b487cbead1bd 100644
--- a/arch/um/os-Linux/sys-i386/registers.c
+++ b/arch/um/os-Linux/sys-i386/registers.c
@@ -5,6 +5,7 @@
  */
 
 #include <errno.h>
+#include <sys/ptrace.h>
 #include <asm/user.h>
 #include "kern_constants.h"
 #include "longjmp.h"