--- x/fs/netfs/write_collect.c
+++ y/fs/netfs/write_collect.c
@@ -548,7 +548,9 @@ void netfs_write_collection_worker(struc
 		return;
 	}
 
+	mutex_lock(&ictx->wb_lock);
 	netfs_collect_write_results(wreq);
+	mutex_unlock(&ictx->wb_lock);
 
 	/* We're done when the app thread has finished posting subreqs and all
 	 * the queues in all the streams are empty.
--- l/net/9p/client.c
+++ c/net/9p/client.c
@@ -1039,7 +1039,7 @@ struct p9_client *p9_client_create(const
 	 * followed by data accessed from userspace by read
 	 */
 	clnt->fcall_cache =
-		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
+		kmem_cache_create_usercopy(client_id, clnt->msize,
 					   0, 0, P9_HDRSZ + 4,
 					   clnt->msize - (P9_HDRSZ + 4),
 					   NULL);