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=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 480DAC4360F for ; Fri, 15 Feb 2019 02:19:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1943F20643 for ; Fri, 15 Feb 2019 02:19:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550197171; bh=75ZFTjNMSYqsmG7YHM7mPv3uqseEzLTA05v0+UDPCX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gidsjYHR8OJSVn8xFdRcmv+47AH30bUYun4+EDHapsUomCobWCqOcPeiCFek/hhSL k6Iov/G+kRqckKC/Bed92JIrRxOez0sP22O3AiPUyVGhRQrD11x5TtQXMJl7klS+xm BrPrOo988P7CdpzXANeln6FlDVu5MBRZWU7Zvvzc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405834AbfBOCPi (ORCPT ); Thu, 14 Feb 2019 21:15:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:55228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391989AbfBOCPe (ORCPT ); Thu, 14 Feb 2019 21:15:34 -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 8F443222D4; Fri, 15 Feb 2019 02:15:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550196933; bh=75ZFTjNMSYqsmG7YHM7mPv3uqseEzLTA05v0+UDPCX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pClDF/jGMt5NOcdhFjRpjAKglS4nHYvb2Af68aKCfG3btS2NPGk1gRo3HfJt6J55A 3dSC38unr8iyWTZkyvGJZ/iacbrKOuoA+iLmGF8z25/DxHzTNdLgRafN9o78KZRgLw MxRqUVCtfiJCqhKKobs+sZLNDmAj66IKXcNSSLXc= 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 4.4 11/20] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive() Date: Thu, 14 Feb 2019 21:15:02 -0500 Message-Id: <20190215021511.179333-11-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190215021511.179333-1-sashal@kernel.org> References: <20190215021511.179333-1-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 ad3c9e96a275..3e6897efe1eb 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -3181,9 +3181,10 @@ 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