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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 40BBFC43381 for ; Fri, 15 Feb 2019 02:22:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1149E20643 for ; Fri, 15 Feb 2019 02:22:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550197337; bh=RetwS2r0EsBBUugiakQd4xYjxPj3kZmd8uZR+VqcxMw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bFQh7ei8ovnulSADFziCYrIfZL3tYXeFzS4MGVyEk8fAeDsdIAKJYIaAM9HnSE4Uz 0DXQ6ZzjuNlsQksZBS7TXuLTw77o6uPqcj5G1QXRE0M02MxY7dVT1ol/6rTpuj61ls CULpeNjeQe6oQXWLMQPGbb00dZIgVgt0yk4nSARc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733181AbfBOCWP (ORCPT ); Thu, 14 Feb 2019 21:22:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:54712 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405283AbfBOCOx (ORCPT ); Thu, 14 Feb 2019 21:14:53 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8583121934; Fri, 15 Feb 2019 02:14:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550196892; bh=RetwS2r0EsBBUugiakQd4xYjxPj3kZmd8uZR+VqcxMw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nsq486aJ+JJc0u3YvNLd4wXTPYVfXsbV9oqdsq4AVnj4PoG7FkAbTGtHAeP8OCMwQ sBV8VWqykbYzQ5Ho0hvctlRp1aTXkk+6b+DVzuO3tp0n0cUg7ztz/YHtk9xlx63ik6 GGFjdVHV6HWNopd7HRkH9QbZ9rrte7UkzD0Dcxl8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ilya Dryomov , Sasha Levin , ceph-devel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 14/27] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive() Date: Thu, 14 Feb 2019 21:14:11 -0500 Message-Id: <20190215021424.178979-14-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190215021424.178979-1-sashal@kernel.org> References: <20190215021424.178979-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ilya Dryomov [ Upstream commit 4aac9228d16458cedcfd90c7fb37211cf3653ac3 ] 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: Sasha Levin --- net/ceph/messenger.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 5a8075d9f2e7..93eb606f7628 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -3186,9 +3186,10 @@ void ceph_con_keepalive(struct ceph_connection *con) 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); -- 2.19.1