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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 B1836C282C2 for ; Wed, 13 Feb 2019 18:56:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 811AA20835 for ; Wed, 13 Feb 2019 18:56:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550084177; bh=yXuLiWmByyPgCYHcAgM/+34pHoS3VqsyYe9dInVwwAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yD9Efq/9oB61yX/LEBFY03/1DeFSxV0qAvCW646mMd+L4I1Oxlb7Ur96ogAxyT+T6 A3iMNsLJBvfGkdaQPy1t6zJP9gb477kXU8wF3s/Gq8/OzZcgagflTpSFQWrfOd6GH7 M7Yru+/foZbao3npE9v9Jbeu7MrSP8LYdVV6ODgI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394345AbfBMS4P (ORCPT ); Wed, 13 Feb 2019 13:56:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:38202 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727324AbfBMSkG (ORCPT ); Wed, 13 Feb 2019 13:40:06 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1F6A2222D6; Wed, 13 Feb 2019 18:40:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550083205; bh=yXuLiWmByyPgCYHcAgM/+34pHoS3VqsyYe9dInVwwAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ynY8dnDOS8fF8eRY+DIUi560NrThqb/Oujt+DDL63DAifI2/2+MeJxCW0jJ3FO99J fiWctbE6bBn8v2OHW4lY1f0I+oamFwb9YXT89FjFYPDJLqlmCFd+abT3j8z3ktqKto R1T7RUDZn7j1fYu9hUs3sqixekJZGAVYkUSGGSeg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+acdeb633f6211ccdf886@syzkaller.appspotmail.com, Ilya Dryomov , Myungho Jung Subject: [PATCH 4.9 21/24] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive() Date: Wed, 13 Feb 2019 19:38:18 +0100 Message-Id: <20190213183649.232203318@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190213183647.333441569@linuxfoundation.org> References: <20190213183647.333441569@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ilya Dryomov commit 4aac9228d16458cedcfd90c7fb37211cf3653ac3 upstream. con_fault() can transition the connection into STANDBY right after ceph_con_keepalive() clears STANDBY in clear_standby(): libceph user thread ceph-msgr worker ceph_con_keepalive() mutex_lock(&con->mutex) clear_standby(con) mutex_unlock(&con->mutex) mutex_lock(&con->mutex) con_fault() ... if KEEPALIVE_PENDING isn't set set state to STANDBY ... mutex_unlock(&con->mutex) set KEEPALIVE_PENDING set WRITE_PENDING This triggers warnings in clear_standby() when either ceph_con_send() or ceph_con_keepalive() get to clearing STANDBY next time. I don't see a reason to condition queue_con() call on the previous value of KEEPALIVE_PENDING, so move the setting of KEEPALIVE_PENDING into the critical section -- unlike WRITE_PENDING, KEEPALIVE_PENDING could have been a non-atomic flag. Reported-by: syzbot+acdeb633f6211ccdf886@syzkaller.appspotmail.com Signed-off-by: Ilya Dryomov Tested-by: Myungho Jung Signed-off-by: Greg Kroah-Hartman --- net/ceph/messenger.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -3186,9 +3186,10 @@ void ceph_con_keepalive(struct ceph_conn dout("con_keepalive %p\n", con); mutex_lock(&con->mutex); clear_standby(con); + con_flag_set(con, CON_FLAG_KEEPALIVE_PENDING); mutex_unlock(&con->mutex); - if (con_flag_test_and_set(con, CON_FLAG_KEEPALIVE_PENDING) == 0 && - con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0) + + if (con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0) queue_con(con); } EXPORT_SYMBOL(ceph_con_keepalive);