Index: sys/kern/kern_intr.c
===================================================================
--- sys/kern/kern_intr.c
+++ sys/kern/kern_intr.c
@@ -286,11 +286,51 @@
 {
 	struct intr_event *ie;
 	va_list ap;
+	int res;
+
+	ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
+	va_start(ap, fmt);
+	res = intr_event_initv(ie, source, flags, irq, pre_ithread,
+	    post_ithread, post_filter, assign_cpu, fmt, ap);
+	va_end(ap);
+
+	if (res != 0) {
+		free(ie, M_ITHREAD);
+		return (res);
+	}
+
+	if (event != NULL)
+		*event = ie;
+	return (res);
+}
+
+int
+intr_event_init(struct intr_event *ie, void *source, int flags, int irq,
+    void (*pre_ithread)(void *), void (*post_ithread)(void *),
+    void (*post_filter)(void *), int (*assign_cpu)(void *, int),
+    const char *fmt, ...)
+{
+	va_list ap;
+	int res;
+
+	va_start(ap, fmt);
+	res = intr_event_initv(ie, source, flags, irq, pre_ithread,
+	    post_ithread, post_filter, assign_cpu, fmt, ap);
+	va_end(ap);
+
+	return (res);
+}
+
+int
+intr_event_initv(struct intr_event *ie, void *source, int flags, int irq,
+    void (*pre_ithread)(void *), void (*post_ithread)(void *),
+    void (*post_filter)(void *), int (*assign_cpu)(void *, int),
+    const char *fmt, __va_list ap)
+{
 
 	/* The only valid flag during creation is IE_SOFT. */
 	if ((flags & ~IE_SOFT) != 0)
 		return (EINVAL);
-	ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
 	ie->ie_source = source;
 	ie->ie_pre_ithread = pre_ithread;
 	ie->ie_post_ithread = post_ithread;
@@ -302,15 +342,11 @@
 	CK_SLIST_INIT(&ie->ie_handlers);
 	mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
 
-	va_start(ap, fmt);
 	vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
-	va_end(ap);
 	strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
 	mtx_lock(&event_lock);
 	TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
 	mtx_unlock(&event_lock);
-	if (event != NULL)
-		*event = ie;
 	CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
 	return (0);
 }
@@ -531,6 +567,15 @@
 
 int
 intr_event_destroy(struct intr_event *ie)
+{
+
+	intr_event_shutdown(ie);
+	free(ie, M_ITHREAD);
+	return (0);
+}
+
+int
+intr_event_shutdown(struct intr_event *ie)
 {
 
 	mtx_lock(&event_lock);
@@ -550,7 +595,6 @@
 	mtx_unlock(&ie->ie_lock);
 	mtx_unlock(&event_lock);
 	mtx_destroy(&ie->ie_lock);
-	free(ie, M_ITHREAD);
 	return (0);
 }
 
Index: sys/sys/interrupt.h
===================================================================
--- sys/sys/interrupt.h
+++ sys/sys/interrupt.h
@@ -180,9 +180,20 @@
 	    void (*post_ithread)(void *), void (*post_filter)(void *),
 	    int (*assign_cpu)(void *, int), const char *fmt, ...)
 	    __printflike(9, 10);
+int     intr_event_init(struct intr_event *event, void *source,
+	    int flags, int irq, void (*pre_ithread)(void *),
+	    void (*post_ithread)(void *), void (*post_filter)(void *),
+	    int (*assign_cpu)(void *, int), const char *fmt, ...)
+	    __printflike(9, 10);
+int     intr_event_initv(struct intr_event *event, void *source,
+	    int flags, int irq, void (*pre_ithread)(void *),
+	    void (*post_ithread)(void *), void (*post_filter)(void *),
+	    int (*assign_cpu)(void *, int), const char *fmt, __va_list)
+	    __printflike(9, 0);
 int	intr_event_describe_handler(struct intr_event *ie, void *cookie,
 	    const char *descr);
 int	intr_event_destroy(struct intr_event *ie);
+int	intr_event_shutdown(struct intr_event *ie);
 int	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
 int	intr_event_remove_handler(void *cookie);
 int	intr_event_suspend_handler(void *cookie);