1 files changed, 1 insertions, 0 deletions
diff --git a/sys/sys/mutex.h b/sys/sys/mutex.h
index 4d3a9d556e3a..54d4088d8e6c 100644
--- a/sys/sys/mutex.h
+++ b/sys/sys/mutex.h
@@ -41,6 +41,7 @@
 #include <machine/bus.h>
 #include <machine/cpufunc.h>
 #include <machine/globals.h>
+#include <sys/proc.h> /* Needed for curproc. */
 #ifndef curproc
 struct proc;
 extern struct proc *curproc;