Index: head/sys/kern/kern_kcov.c
===================================================================
--- head/sys/kern/kern_kcov.c
+++ head/sys/kern/kern_kcov.c
@@ -58,6 +58,7 @@
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
+#include <vm/vm_param.h>
 
 MALLOC_DEFINE(M_KCOV_INFO, "kcovinfo", "KCOV info type");
 
@@ -347,6 +348,7 @@
 	    info->mmap != false)
 		return (EINVAL);
 
+	vm_object_reference(info->bufobj);
 	info->mmap = true;
 	*offset = 0;
 	*object = info->bufobj;
@@ -393,13 +395,26 @@
 static void
 kcov_free(struct kcov_info *info)
 {
+	vm_page_t m;
+	size_t i;
 
 	if (info->kvaddr != 0) {
 		pmap_qremove(info->kvaddr, info->bufsize / PAGE_SIZE);
 		kva_free(info->kvaddr, info->bufsize);
 	}
-	if (info->bufobj != NULL && !info->mmap)
+	if (info->bufobj != NULL) {
+		VM_OBJECT_WLOCK(info->bufobj);
+		m = vm_page_lookup(info->bufobj, 0);
+		for (i = 0; i < info->bufsize / PAGE_SIZE; i++) {
+			vm_page_lock(m);
+			vm_page_unwire_noq(m);
+			vm_page_unlock(m);
+
+			m = vm_page_next(m);
+		}
+		VM_OBJECT_WUNLOCK(info->bufobj);
 		vm_object_deallocate(info->bufobj);
+	}
 	free(info, M_KCOV_INFO);
 }