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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS 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 80B63C169C4 for ; Tue, 29 Jan 2019 19:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 417CC20856 for ; Tue, 29 Jan 2019 19:41:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548790906; bh=IxMRkEEI2Jwl6Fhea3wm3+o/Xr3W8Nt2OtJl/uT4yCU=; h=Subject:To:Cc:From:Date:List-ID:From; b=zyy9Rt01mh3XAmaWQ/Ze0Z6CIQb1np4fHiCsNYEUQOygB1hIWcSfW9b99fjBLn7tZ dGzI+naNDtNMSnCs2M9PUq3lozbgQ1G6Sx4kupCP7yEN0I1LPb4RofJxdZamAYqT93 bb+84T8FbWfPxcOTeCAP99Q4PHQi6bQXLATvH+V8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727056AbfA2Tlp (ORCPT ); Tue, 29 Jan 2019 14:41:45 -0500 Received: from new1-smtp.messagingengine.com ([66.111.4.221]:59663 "EHLO new1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726828AbfA2Tlp (ORCPT ); Tue, 29 Jan 2019 14:41:45 -0500 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailnew.nyi.internal (Postfix) with ESMTP id 14469171B4; Tue, 29 Jan 2019 14:41:42 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Tue, 29 Jan 2019 14:41:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=WptU1G H9dwJA79TRQLPXX2GtwnYLOcIVw+HX5FnGk0g=; b=l7YUPZGuFZYx2XWA8v87qe QvAjYQ/pDFkrbp6PI7GiZMfW8FfrsWmFPYdWOjIt3+10D+NVQcoeQnqYVXmWphXD PY0B5w4ZQGXsQqXkjdOFdxr6dZYd94RlhAqx8/5GE3WBDEkk5SmtuWfsBZpN3my/ 2cBm9Vq353JWHSiHkQ1cqCwC8Tm8EskLBcX0uXLglGRAtDH2YZwA3lhhglbVorv4 3XIM8xmV/zDe91Kou+7UTGxsMCd2pfwUKFX5HMZqMmMbBJuaBA02O1PYA0Yam88n 9ps2fM6NdVV5JFJO3NAGGWNFg3yAOY2m1rQ6iSSnWcnxs9q9Q4cI5mp+DtDd0CrQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedtledrjedvgddufedtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfquhhtnecuuegrihhlohhuthemucef tddtnecuogfuphgrmhfkphculdeftddtmdenucfjughrpefuvffhfffkgggtgfesthekre dttddtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdr ohhrgheqnecukfhppeekfedrkeeirdekledruddtjeenucfrrghrrghmpehmrghilhhfrh homhepghhrvghgsehkrhhorghhrdgtohhmnecuvehluhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: from localhost (5356596b.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 345CE10311; Tue, 29 Jan 2019 14:41:41 -0500 (EST) Subject: FAILED: patch "[PATCH] CIFS: Do not reconnect TCP session in add_credits()" failed to apply to 4.9-stable tree To: pshilov@microsoft.com, lsahlber@redhat.com, stable@vger.kernel.org, stfrench@microsoft.com Cc: From: Date: Tue, 29 Jan 2019 20:41:38 +0100 Message-ID: <1548790898147243@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From ef68e831840c40c7d01b328b3c0f5d8c4796c232 Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky Date: Fri, 18 Jan 2019 17:25:36 -0800 Subject: [PATCH] CIFS: Do not reconnect TCP session in add_credits() When executing add_credits() we currently call cifs_reconnect() if the number of credits is zero and there are no requests in flight. In this case we may call cifs_reconnect() recursively twice and cause memory corruption given the following sequence of functions: mid1.callback() -> add_credits() -> cifs_reconnect() -> -> mid2.callback() -> add_credits() -> cifs_reconnect(). Fix this by avoiding to call cifs_reconnect() in add_credits() and checking for zero credits in the demultiplex thread. Cc: Signed-off-by: Pavel Shilovsky Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 683310f26171..8463c940e0e5 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -720,6 +720,21 @@ server_unresponsive(struct TCP_Server_Info *server) return false; } +static inline bool +zero_credits(struct TCP_Server_Info *server) +{ + int val; + + spin_lock(&server->req_lock); + val = server->credits + server->echo_credits + server->oplock_credits; + if (server->in_flight == 0 && val == 0) { + spin_unlock(&server->req_lock); + return true; + } + spin_unlock(&server->req_lock); + return false; +} + static int cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg) { @@ -732,6 +747,12 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg) for (total_read = 0; msg_data_left(smb_msg); total_read += length) { try_to_freeze(); + /* reconnect if no credits and no requests in flight */ + if (zero_credits(server)) { + cifs_reconnect(server); + return -ECONNABORTED; + } + if (server_unresponsive(server)) return -ECONNABORTED; if (cifs_rdma_enabled(server) && server->smbd_conn) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 1d3ce127b02e..fa8d2e1076c8 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -34,6 +34,7 @@ #include "cifs_ioctl.h" #include "smbdirect.h" +/* Change credits for different ops and return the total number of credits */ static int change_conf(struct TCP_Server_Info *server) { @@ -41,17 +42,15 @@ change_conf(struct TCP_Server_Info *server) server->oplock_credits = server->echo_credits = 0; switch (server->credits) { case 0: - return -1; + return 0; case 1: server->echoes = false; server->oplocks = false; - cifs_dbg(VFS, "disabling echoes and oplocks\n"); break; case 2: server->echoes = true; server->oplocks = false; server->echo_credits = 1; - cifs_dbg(FYI, "disabling oplocks\n"); break; default: server->echoes = true; @@ -64,14 +63,15 @@ change_conf(struct TCP_Server_Info *server) server->echo_credits = 1; } server->credits -= server->echo_credits + server->oplock_credits; - return 0; + return server->credits + server->echo_credits + server->oplock_credits; } static void smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add, const int optype) { - int *val, rc = 0; + int *val, rc = -1; + spin_lock(&server->req_lock); val = server->ops->get_credits_field(server, optype); @@ -101,8 +101,26 @@ smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add, } spin_unlock(&server->req_lock); wake_up(&server->request_q); - if (rc) - cifs_reconnect(server); + + if (server->tcpStatus == CifsNeedReconnect) + return; + + switch (rc) { + case -1: + /* change_conf hasn't been executed */ + break; + case 0: + cifs_dbg(VFS, "Possible client or server bug - zero credits\n"); + break; + case 1: + cifs_dbg(VFS, "disabling echoes and oplocks\n"); + break; + case 2: + cifs_dbg(FYI, "disabling oplocks\n"); + break; + default: + cifs_dbg(FYI, "add %u credits total=%d\n", add, rc); + } } static void