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=-6.1 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 2B877C43381 for ; Mon, 18 Feb 2019 14:06:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEF4E21908 for ; Mon, 18 Feb 2019 14:06:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498772; bh=HEB9v7A5hYtuNEOt3CVHtd+W6AuzMhvXUs1pngTDgTA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AyBEHyL0LxlTkqb/RH6xHtfjygOeL+TrJ6YbOGbDBLPlflMqCxFMYlRrdWJo++tc5 m7W/y3KVoJq9cIEIgxpU8WduOMPjGKK/G27gFGQpw+ipsQw9LsRYFfQ0NeG+j+WmiW QTY+Dpilb+Ccgl+l0BJcPDUsWUiCDvdyo82F9e2k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388553AbfBROGK (ORCPT ); Mon, 18 Feb 2019 09:06:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:49126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390327AbfBROGG (ORCPT ); Mon, 18 Feb 2019 09:06:06 -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 4759221902; Mon, 18 Feb 2019 14:06:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498765; bh=HEB9v7A5hYtuNEOt3CVHtd+W6AuzMhvXUs1pngTDgTA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dnFHTQZmBp/CLB2uQMNtHNjQXGtJKGoIFG0zS0M7Vlm6tbytRwA/uppFdm01lfNC/ o5Kz/HDY44SzZkGwgRROCpqYjuVaF9983jeBkVkaA4mYks+3XMj3Ox+SJ8pLSf97fi bB6S0bXDuo6tKzJ39ckmwa/uwkNQFNwvndlJjXAQ= 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 4.4 114/143] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive() Date: Mon, 18 Feb 2019 14:44:02 +0100 Message-Id: <20190218133533.184728207@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133529.099444112@linuxfoundation.org> References: <20190218133529.099444112@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 4.4-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 @@ -3181,9 +3181,10 @@ 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);