From patchwork Mon May 8 22:17:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 9716775 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2121C6035D for ; Mon, 8 May 2017 22:17:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1360C2624A for ; Mon, 8 May 2017 22:17:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 03B9C269DA; Mon, 8 May 2017 22:17:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 64FA12624A for ; Mon, 8 May 2017 22:17:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751115AbdEHWRt (ORCPT ); Mon, 8 May 2017 18:17:49 -0400 Received: from fieldses.org ([173.255.197.46]:57152 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbdEHWRs (ORCPT ); Mon, 8 May 2017 18:17:48 -0400 Received: by fieldses.org (Postfix, from userid 2815) id B5B6D1C96; Mon, 8 May 2017 18:17:47 -0400 (EDT) Date: Mon, 8 May 2017 18:17:47 -0400 To: linux-nfs@vger.kernel.org Subject: [PATCH] lockd: fix lockd shutdown race Message-ID: <20170508221747.GA6289@fieldses.org> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "J. Bruce Fields" As reported by David Jeffery: "a signal was sent to lockd while lockd was shutting down from a request to stop nfs. The signal causes lockd to call restart_grace() which puts the lockd_net structure on the grace list. If this signal is received at the wrong time, it will occur after lockd_down_net() has called locks_end_grace() but before lockd_down_net() stops the lockd thread. This leads to lockd putting the lockd_net structure back on the grace list, then exiting without anything removing it from the list." So, perform the final locks_end_grace() from the the lockd thread; this ensures it's serialized with respect to restart_grace(). Reported-by: David Jeffery Signed-off-by: J. Bruce Fields --- fs/lockd/svc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index e7c8b9c76e48..5d481e8a1b5d 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -132,6 +132,8 @@ lockd(void *vrqstp) { int err = 0; struct svc_rqst *rqstp = vrqstp; + struct net *net = &init_net; + struct lockd_net *ln = net_generic(net, lockd_net_id); /* try_to_freeze() is called from svc_recv() */ set_freezable(); @@ -176,6 +178,8 @@ lockd(void *vrqstp) if (nlmsvc_ops) nlmsvc_invalidate_all(); nlm_shutdown_hosts(); + cancel_delayed_work_sync(&ln->grace_period_end); + locks_end_grace(&ln->lockd_manager); return 0; } @@ -270,8 +274,6 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net) if (ln->nlmsvc_users) { if (--ln->nlmsvc_users == 0) { nlm_shutdown_hosts_net(net); - cancel_delayed_work_sync(&ln->grace_period_end); - locks_end_grace(&ln->lockd_manager); svc_shutdown_net(serv, net); dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net); }