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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 66983C07520 for ; Thu, 13 Sep 2018 13:36:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27CDC20854 for ; Thu, 13 Sep 2018 13:36:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 27CDC20854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729223AbeIMSqK (ORCPT ); Thu, 13 Sep 2018 14:46:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59300 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727009AbeIMSqK (ORCPT ); Thu, 13 Sep 2018 14:46:10 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id D4400D18; Thu, 13 Sep 2018 13:36:38 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tomas Bortoli , syzbot+735d926e9d1317c3310c@syzkaller.appspotmail.com, Yiwen Jiang , "David S. Miller" , Dominique Martinet , Sasha Levin Subject: [PATCH 4.9 35/78] net/9p/trans_fd.c: fix race by holding the lock Date: Thu, 13 Sep 2018 15:31:22 +0200 Message-Id: <20180913131809.578378646@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180913131805.732342940@linuxfoundation.org> References: <20180913131805.732342940@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tomas Bortoli [ Upstream commit 9f476d7c540cb57556d3cc7e78704e6cd5100f5f ] It may be possible to run p9_fd_cancel() with a deleted req->req_list and incur in a double del. To fix hold the client->lock while changing the status, so the other threads will be synchronized. Link: http://lkml.kernel.org/r/20180723184253.6682-1-tomasbortoli@gmail.com Signed-off-by: Tomas Bortoli Reported-by: syzbot+735d926e9d1317c3310c@syzkaller.appspotmail.com To: Eric Van Hensbergen To: Ron Minnich To: Latchesar Ionkov Cc: Yiwen Jiang Cc: David S. Miller Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/9p/trans_fd.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -195,15 +195,14 @@ static void p9_mux_poll_stop(struct p9_c static void p9_conn_cancel(struct p9_conn *m, int err) { struct p9_req_t *req, *rtmp; - unsigned long flags; LIST_HEAD(cancel_list); p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err); - spin_lock_irqsave(&m->client->lock, flags); + spin_lock(&m->client->lock); if (m->err) { - spin_unlock_irqrestore(&m->client->lock, flags); + spin_unlock(&m->client->lock); return; } @@ -215,7 +214,6 @@ static void p9_conn_cancel(struct p9_con list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { list_move(&req->req_list, &cancel_list); } - spin_unlock_irqrestore(&m->client->lock, flags); list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); @@ -224,6 +222,7 @@ static void p9_conn_cancel(struct p9_con req->t_err = err; p9_client_cb(m->client, req, REQ_STATUS_ERROR); } + spin_unlock(&m->client->lock); } static int @@ -379,8 +378,9 @@ static void p9_read_work(struct work_str if (m->req->status != REQ_STATUS_ERROR) status = REQ_STATUS_RCVD; list_del(&m->req->req_list); - spin_unlock(&m->client->lock); + /* update req->status while holding client->lock */ p9_client_cb(m->client, m->req, status); + spin_unlock(&m->client->lock); m->rc.sdata = NULL; m->rc.offset = 0; m->rc.capacity = 0;