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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 25629C433E1 for ; Thu, 20 Aug 2020 12:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0212E2078B for ; Thu, 20 Aug 2020 12:18:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597925914; bh=WBgfNVb4k44s9KC7OFjmYwafkNkP4GWt5fO3r7F+LYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yNvqYy8BkrS5X+O0tXoNPzTV+D3r07wFFF4CjK0uM2/OrIpurAvbHuwKVGnlu8kzy HIHYhWciGE+V2pB1mpWGdt1KTPcm2hRWSQzhKK46H08SPfNkBWBuMw+DrbMzUK8+lR RqtgE6/tm5RQlYvlPWoZEfENbXNhOFBapVVRJKNU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730622AbgHTMSK (ORCPT ); Thu, 20 Aug 2020 08:18:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:39984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726925AbgHTJ4d (ORCPT ); Thu, 20 Aug 2020 05:56:33 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 C38832067C; Thu, 20 Aug 2020 09:56:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917393; bh=WBgfNVb4k44s9KC7OFjmYwafkNkP4GWt5fO3r7F+LYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dohGRD9tu4qYSUdsX/lHBQr3vkGpgRn/aSTQs+9BNJM2XZK7oPzGyiD1/593zN1d4 CpQTUfx56KapxdX/sK5C8mlXPKZqpVo8jgz/CBkdz5DjQM2JeAsPbFXR/l8kMIpQSK VIW8UtJCqFqgczE1zo5uV7DJMl6BGIYtPrhmuqPk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+77a25acfa0382e06ab23@syzkaller.appspotmail.com, Wang Hai , Dominique Martinet , Sasha Levin Subject: [PATCH 4.9 016/212] 9p/trans_fd: Fix concurrency del of req_list in p9_fd_cancelled/p9_read_work Date: Thu, 20 Aug 2020 11:19:49 +0200 Message-Id: <20200820091603.156368680@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091602.251285210@linuxfoundation.org> References: <20200820091602.251285210@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: Wang Hai [ Upstream commit 74d6a5d5662975aed7f25952f62efbb6f6dadd29 ] p9_read_work and p9_fd_cancelled may be called concurrently. In some cases, req->req_list may be deleted by both p9_read_work and p9_fd_cancelled. We can fix it by ignoring replies associated with a cancelled request and ignoring cancelled request if message has been received before lock. Link: http://lkml.kernel.org/r/20200612090833.36149-1-wanghai38@huawei.com Fixes: 60ff779c4abb ("9p: client: remove unused code and any reference to "cancelled" function") Cc: # v3.12+ Reported-by: syzbot+77a25acfa0382e06ab23@syzkaller.appspotmail.com Signed-off-by: Wang Hai Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- net/9p/trans_fd.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 91f71958c2e16..b0f47563f0bf3 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -377,6 +377,10 @@ static void p9_read_work(struct work_struct *work) if (m->req->status == REQ_STATUS_SENT) { list_del(&m->req->req_list); p9_client_cb(m->client, m->req, REQ_STATUS_RCVD); + } else if (m->req->status == REQ_STATUS_FLSHD) { + /* Ignore replies associated with a cancelled request. */ + p9_debug(P9_DEBUG_TRANS, + "Ignore replies associated with a cancelled request\n"); } else { spin_unlock(&m->client->lock); p9_debug(P9_DEBUG_ERROR, @@ -717,11 +721,20 @@ static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req) { p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); + spin_lock(&client->lock); + /* Ignore cancelled request if message has been received + * before lock. + */ + if (req->status == REQ_STATUS_RCVD) { + spin_unlock(&client->lock); + return 0; + } + /* we haven't received a response for oldreq, * remove it from the list. */ - spin_lock(&client->lock); list_del(&req->req_list); + req->status = REQ_STATUS_FLSHD; spin_unlock(&client->lock); return 0; -- 2.25.1