diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 6893c8afd199..4125781a48e2 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -3193,8 +3193,11 @@ bufdone(struct buf *bp)
 			iosize -= resid;
 		}
 		vm_page_unlock_queues();
-		if (obj)
+		if (obj != NULL) {
+			VM_OBJECT_LOCK(obj);
 			vm_object_pip_wakeupn(obj, 0);
+			VM_OBJECT_UNLOCK(obj);
+		}
 	}
 
 	/*
@@ -3231,6 +3234,7 @@ vfs_unbusy_pages(struct buf * bp)
 		vm_object_t obj;
 
 		obj = bp->b_object;
+		VM_OBJECT_LOCK(obj);
 		vm_page_lock_queues();
 		for (i = 0; i < bp->b_npages; i++) {
 			vm_page_t m = bp->b_pages[i];
@@ -3249,6 +3253,7 @@ vfs_unbusy_pages(struct buf * bp)
 		}
 		vm_page_unlock_queues();
 		vm_object_pip_wakeupn(obj, 0);
+		VM_OBJECT_UNLOCK(obj);
 	}
 }
 
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 0fb5d2203113..997e682dbf4e 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -1613,8 +1613,11 @@ swp_pager_async_iodone(bp)
 	 * adjust pip.  NOTE: the original parent may still have its own
 	 * pip refs on the object.
 	 */
-	if (object)
+	if (object != NULL) {
+		VM_OBJECT_LOCK(object);
 		vm_object_pip_wakeupn(object, bp->b_npages);
+		VM_OBJECT_UNLOCK(object);
+	}
 
 	/*
 	 * release the physical I/O buffer
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index a079d83abf1d..4f784b0851c9 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -296,6 +296,7 @@ void
 vm_object_pip_wakeupn(vm_object_t object, short i)
 {
 	GIANT_REQUIRED;
+	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	if (i)
 		object->paging_in_progress -= i;
 	if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index 4f4f77b9431c..9dd0ab95d1be 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -171,6 +171,8 @@ extern vm_object_t kernel_object;	/* the single kernel object */
 extern vm_object_t kmem_object;
 
 #define	VM_OBJECT_LOCK(object)		mtx_lock(&(object)->mtx)
+#define	VM_OBJECT_LOCK_ASSERT(object, type) \
+					mtx_assert(&(object)->mtx, (type))
 #define	VM_OBJECT_UNLOCK(object)	mtx_unlock(&(object)->mtx)
 
 #define	vm_object_lock(object) \