From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05ECFC433FE for ; Fri, 24 Sep 2021 12:58:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD8DB615E0 for ; Fri, 24 Sep 2021 12:58:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345843AbhIXM7e (ORCPT ); Fri, 24 Sep 2021 08:59:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:57332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345502AbhIXM62 (ORCPT ); Fri, 24 Sep 2021 08:58:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0F70161359; Fri, 24 Sep 2021 12:52:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632487949; bh=meQaol9N4At2p4QAx5S9vy6GohX72d19BCZa0U+/tqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xrLmIogdNYbxvXd+W6HQq9ucv+4C5AE5iMVFwDgMv9wP6VQuTU0zcoTowOBAdvOb3 baOrpJL/PabuzUEzQsKWCcrfZwiC2CqtAqQRPynXTg+H4vX7JiYmk/Wer6BTRbKro6 U0fqzt2CnVGyWO46zaBTS8yzYwLnxP9zMw56WCYs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeff Layton , Xiubo Li , Ilya Dryomov Subject: [PATCH 5.14 024/100] ceph: cancel delayed work instead of flushing on mdsc teardown Date: Fri, 24 Sep 2021 14:43:33 +0200 Message-Id: <20210924124342.251566373@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210924124341.214446495@linuxfoundation.org> References: <20210924124341.214446495@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jeff Layton commit b4002173b7989588b6feaefc42edaf011b596782 upstream. The first thing metric_delayed_work does is check mdsc->stopping, and then return immediately if it's set. That's good since we would have already torn down the metric structures at this point, otherwise, but there is no locking around mdsc->stopping. It's possible that the ceph_metric_destroy call could race with the delayed_work, in which case we could end up with the delayed_work accessing destroyed percpu variables. At this point in the mdsc teardown, the "stopping" flag has already been set, so there's no benefit to flushing the work. Move the work cancellation in ceph_metric_destroy ahead of the percpu variable destruction, and eliminate the flush_delayed_work call in ceph_mdsc_destroy. Fixes: 18f473b384a6 ("ceph: periodically send perf metrics to MDSes") Signed-off-by: Jeff Layton Reviewed-by: Xiubo Li Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/mds_client.c | 1 - fs/ceph/metric.c | 4 ++-- 2 files changed, 2 insertions(+), 3 deletions(-) --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -4912,7 +4912,6 @@ void ceph_mdsc_destroy(struct ceph_fs_cl ceph_metric_destroy(&mdsc->metric); - flush_delayed_work(&mdsc->metric.delayed_work); fsc->mdsc = NULL; kfree(mdsc); dout("mdsc_destroy %p done\n", mdsc); --- a/fs/ceph/metric.c +++ b/fs/ceph/metric.c @@ -302,6 +302,8 @@ void ceph_metric_destroy(struct ceph_cli if (!m) return; + cancel_delayed_work_sync(&m->delayed_work); + percpu_counter_destroy(&m->total_inodes); percpu_counter_destroy(&m->opened_inodes); percpu_counter_destroy(&m->i_caps_mis); @@ -309,8 +311,6 @@ void ceph_metric_destroy(struct ceph_cli percpu_counter_destroy(&m->d_lease_mis); percpu_counter_destroy(&m->d_lease_hit); - cancel_delayed_work_sync(&m->delayed_work); - ceph_put_mds_session(m->session); }