From nobody Wed Sep 3 05:56:35 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E105AC38A2D for ; Mon, 24 Oct 2022 12:18:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233223AbiJXMSX (ORCPT ); Mon, 24 Oct 2022 08:18:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233129AbiJXMQ2 (ORCPT ); Mon, 24 Oct 2022 08:16:28 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02F238111F; Mon, 24 Oct 2022 04:56:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BA9AB61257; Mon, 24 Oct 2022 11:56:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCEF1C433C1; Mon, 24 Oct 2022 11:56:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666612590; bh=XvMEixgT9BGjJ6ja9ttKqMsTyosvpjjoTnATBzIPtLI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sr0v2DSNSuxlRxTLOlpgk/J2JaZ9qHC/KlC4qrXAUsZpo8RCUTbPwBMWtvbORqCob mLu7pnJjPX8jy4hm4I0tawz2JsBcn6v0DtF73WfrgQQt8D7TIXcAq/5rbX02ZQyE0/ 9sx4wsqVX2ItyQVEfk1nHA0xGHVi1oZoEzKsnRSA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Aring , David Teigland Subject: [PATCH 4.19 044/229] fs: dlm: fix race between test_bit() and queue_work() Date: Mon, 24 Oct 2022 13:29:23 +0200 Message-Id: <20221024113000.523018503@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112959.085534368@linuxfoundation.org> References: <20221024112959.085534368@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Alexander Aring commit eef6ec9bf390e836a6c4029f3620fe49528aa1fe upstream. This patch fixes a race by using ls_cb_mutex around the bit operations and conditional code blocks for LSFL_CB_DELAY. The function dlm_callback_stop() expects to stop all callbacks and flush all currently queued onces. The set_bit() is not enough because there can still be queue_work() after the workqueue was flushed. To avoid queue_work() after set_bit(), surround both by ls_cb_mutex. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Greg Kroah-Hartman --- fs/dlm/ast.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/dlm/ast.c +++ b/fs/dlm/ast.c @@ -200,13 +200,13 @@ void dlm_add_cb(struct dlm_lkb *lkb, uin if (!prev_seq) { kref_get(&lkb->lkb_ref); =20 + mutex_lock(&ls->ls_cb_mutex); if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) { - mutex_lock(&ls->ls_cb_mutex); list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay); - mutex_unlock(&ls->ls_cb_mutex); } else { queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work); } + mutex_unlock(&ls->ls_cb_mutex); } out: mutex_unlock(&lkb->lkb_cb_mutex); @@ -286,7 +286,9 @@ void dlm_callback_stop(struct dlm_ls *ls =20 void dlm_callback_suspend(struct dlm_ls *ls) { + mutex_lock(&ls->ls_cb_mutex); set_bit(LSFL_CB_DELAY, &ls->ls_flags); + mutex_unlock(&ls->ls_cb_mutex); =20 if (ls->ls_callback_wq) flush_workqueue(ls->ls_callback_wq);