diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index c3c6e5afea10..a6165cf1922c 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -524,7 +524,9 @@ cluster_callback(bp)
 	if (bp->b_ioflags & BIO_ERROR)
 		error = bp->b_error;
 
+	VM_LOCK_GIANT();
 	pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
+	VM_UNLOCK_GIANT();
 	/*
 	 * Move memory from the large cluster buffer into the component
 	 * buffers and mark IO as done on these.