diff --git a/vg_kerneliface.h b/vg_kerneliface.h
index 062f1e4..02dabc0 100644
--- a/vg_kerneliface.h
+++ b/vg_kerneliface.h
@@ -118,6 +118,7 @@
 #define VKI_SIGKILL          9
 #define VKI_SIGSTOP         19
 #define VKI_SIGTERM         15
+#define VKI_SIGUSR1         10
 
 /* The following are copied from /usr/include/bits/mman.h, which in
    turn claims to have got them from the kernel headers. */