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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 26E2ECA9EC9 for ; Mon, 4 Nov 2019 22:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F013B2084D for ; Mon, 4 Nov 2019 22:07:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572905257; bh=vk8+b7SiuqvG0ZON2WuQ93hgwJbDz+Km6Ck2/nY0Gbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=K/EWI2/Ol+E95i7k2ZNQm4tAg0CuISNKc7jmWrNjgzehAxufc29foOK4kccSz6wi9 c0m/NhSD8IoUblbEhue9/SO1cqXRvYhsJq8WtRQSIx3YhFjsy0P2sGbK/5to50TfPB cfR/ZVslTTeyZgdoixfsCglsemHeSMjmEkozmFQs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390145AbfKDWHf (ORCPT ); Mon, 4 Nov 2019 17:07:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:40080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389306AbfKDWHd (ORCPT ); Mon, 4 Nov 2019 17:07:33 -0500 Received: from localhost (6.204-14-84.ripe.coltfrance.com [84.14.204.6]) (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 0270E2084D; Mon, 4 Nov 2019 22:07:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572905252; bh=vk8+b7SiuqvG0ZON2WuQ93hgwJbDz+Km6Ck2/nY0Gbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tYNd4knRHVwZIaNWgxZSaTXcZ1vZL9XCOcT5zaRCGA08pYE4Km4cti5NB18sy9joX KKUZzg94TolUXGJHbjILkhBLRep0pFsr894IvkpSfdTOYc3bj59RgycEeAg/wjVzxL xwR0I0QI6uo0AMLsJkh6r2B8XEu2CVs7OzSPvVoc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Benjamin Coddington , Anna Schumaker , Sasha Levin Subject: [PATCH 5.3 080/163] SUNRPC: fix race to sk_err after xs_error_report Date: Mon, 4 Nov 2019 22:44:30 +0100 Message-Id: <20191104212146.103618988@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191104212140.046021995@linuxfoundation.org> References: <20191104212140.046021995@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Benjamin Coddington [ Upstream commit af84537dbd1b39505d1f3d8023029b4a59666513 ] Since commit 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context") there has been a race to the value of the sk_err if both XPRT_SOCK_WAKE_ERROR and XPRT_SOCK_WAKE_DISCONNECT are set. In that case, we may end up losing the sk_err value that existed when xs_error_report was called. Fix this by reverting to the previous behavior: instead of using SO_ERROR to retrieve the value at a later time (which might also return sk_err_soft), copy the sk_err value onto struct sock_xprt, and use that value to wake pending tasks. Signed-off-by: Benjamin Coddington Fixes: 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context") Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- include/linux/sunrpc/xprtsock.h | 1 + net/sunrpc/xprtsock.c | 17 ++++++++--------- 2 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/sunrpc/xprtsock.h b/include/linux/sunrpc/xprtsock.h index 7638dbe7bc500..a940de03808dd 100644 --- a/include/linux/sunrpc/xprtsock.h +++ b/include/linux/sunrpc/xprtsock.h @@ -61,6 +61,7 @@ struct sock_xprt { struct mutex recv_mutex; struct sockaddr_storage srcaddr; unsigned short srcport; + int xprt_err; /* * UDP socket buffer size parameters diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index e2176c167a579..4e0b5bed6c737 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1243,19 +1243,21 @@ static void xs_error_report(struct sock *sk) { struct sock_xprt *transport; struct rpc_xprt *xprt; - int err; read_lock_bh(&sk->sk_callback_lock); if (!(xprt = xprt_from_sock(sk))) goto out; transport = container_of(xprt, struct sock_xprt, xprt); - err = -sk->sk_err; - if (err == 0) + transport->xprt_err = -sk->sk_err; + if (transport->xprt_err == 0) goto out; dprintk("RPC: xs_error_report client %p, error=%d...\n", - xprt, -err); - trace_rpc_socket_error(xprt, sk->sk_socket, err); + xprt, -transport->xprt_err); + trace_rpc_socket_error(xprt, sk->sk_socket, transport->xprt_err); + + /* barrier ensures xprt_err is set before XPRT_SOCK_WAKE_ERROR */ + smp_mb__before_atomic(); xs_run_error_worker(transport, XPRT_SOCK_WAKE_ERROR); out: read_unlock_bh(&sk->sk_callback_lock); @@ -2470,7 +2472,6 @@ static void xs_wake_write(struct sock_xprt *transport) static void xs_wake_error(struct sock_xprt *transport) { int sockerr; - int sockerr_len = sizeof(sockerr); if (!test_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state)) return; @@ -2479,9 +2480,7 @@ static void xs_wake_error(struct sock_xprt *transport) goto out; if (!test_and_clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state)) goto out; - if (kernel_getsockopt(transport->sock, SOL_SOCKET, SO_ERROR, - (char *)&sockerr, &sockerr_len) != 0) - goto out; + sockerr = xchg(&transport->xprt_err, 0); if (sockerr < 0) xprt_wake_pending_tasks(&transport->xprt, sockerr); out: -- 2.20.1