diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index c41fba0..b6f796f 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -57,6 +57,14 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/uma.h>
 
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+
+#include <ddb/ddb.h>
+#include <ddb/db_watch.h>
+
+
 SYSCTL_NODE(_hw, OID_AUTO, bus, CTLFLAG_RW, NULL, NULL);
 SYSCTL_NODE(, OID_AUTO, dev, CTLFLAG_RW, NULL, NULL);
 
@@ -542,6 +550,7 @@ devctl_queue_data_f(char *data, int flags)
 {
 	struct dev_event_info *n1 = NULL, *n2 = NULL;
 	struct proc *p;
+	char *wp;
 
 	if (strlen(data) == 0)
 		goto out;
@@ -550,6 +559,13 @@ devctl_queue_data_f(char *data, int flags)
 	n1 = malloc(sizeof(*n1), M_BUS, flags);
 	if (n1 == NULL)
 		goto out;
+	if (n1 == (void *)0xced40080) {
+		wp = (char *)n1;
+		wp -= (16 + sizeof(u_long));
+		if (db_md_set_watchpoint((u_long)wp, 4) < 0)
+			panic("could not set watchpoint");
+	}
+
 	n1->dei_data = data;
 	mtx_lock(&devsoftc.mtx);
 	if (devctl_queue_length == 0) {