From patchwork Thu Dec 6 19:14:34 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 10716665 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C436613BF for ; Thu, 6 Dec 2018 19:15:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B69842F02D for ; Thu, 6 Dec 2018 19:15:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAF322F07F; Thu, 6 Dec 2018 19:15:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27C802F02D for ; Thu, 6 Dec 2018 19:15:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725948AbeLFTPd (ORCPT ); Thu, 6 Dec 2018 14:15:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32982 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbeLFTPd (ORCPT ); Thu, 6 Dec 2018 14:15:33 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AF5D3308424B; Thu, 6 Dec 2018 19:15:32 +0000 (UTC) Received: from localhost (ovpn-117-90.ams2.redhat.com [10.36.117.90]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1172819C7F; Thu, 6 Dec 2018 19:15:27 +0000 (UTC) From: Stefan Hajnoczi To: kvm@vger.kernel.org Cc: "Michael S. Tsirkin" , netdev@vger.kernel.org, Maximilian Riemensberger , Graham Whaley , Stefan Hajnoczi Subject: [PATCH] vhost/vsock: fix reset orphans race with close timeout Date: Thu, 6 Dec 2018 19:14:34 +0000 Message-Id: <20181206191434.15448-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 06 Dec 2018 19:15:32 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If a local process has closed a connected socket and hasn't received a RST packet yet, then the socket remains in the table until a timeout expires. When a vhost_vsock instance is released with the timeout still pending, the socket is never freed because vhost_vsock has already set the SOCK_DONE flag. Check if the close timer is pending and let it close the socket. This prevents the race which can leak sockets. Reported-by: Maximilian Riemensberger Cc: Graham Whaley Signed-off-by: Stefan Hajnoczi --- drivers/vhost/vsock.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 34bc3ab40c6d..731e2ea2aeca 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -563,13 +563,21 @@ static void vhost_vsock_reset_orphans(struct sock *sk) * executing. */ - if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) { - sock_set_flag(sk, SOCK_DONE); - vsk->peer_shutdown = SHUTDOWN_MASK; - sk->sk_state = SS_UNCONNECTED; - sk->sk_err = ECONNRESET; - sk->sk_error_report(sk); - } + /* If the peer is still valid, no need to reset connection */ + if (vhost_vsock_get(vsk->remote_addr.svm_cid)) + return; + + /* If the close timeout is pending, let it expire. This avoids races + * with the timeout callback. + */ + if (vsk->close_work_scheduled) + return; + + sock_set_flag(sk, SOCK_DONE); + vsk->peer_shutdown = SHUTDOWN_MASK; + sk->sk_state = SS_UNCONNECTED; + sk->sk_err = ECONNRESET; + sk->sk_error_report(sk); } static int vhost_vsock_dev_release(struct inode *inode, struct file *file)