diff --git a/sys/kern/subr_stack.c b/sys/kern/subr_stack.c
index c2b2cc0156bf..0cd6909543e6 100644
--- a/sys/kern/subr_stack.c
+++ b/sys/kern/subr_stack.c
@@ -40,7 +40,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/stack.h>
 #include <sys/systm.h>
 
-MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
+static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
 
 static void stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
 	    long *offset);