From patchwork Fri Jun 28 12:36:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Garzarella X-Patchwork-Id: 1124188 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45Zx9l25NZz9sCJ for ; Fri, 28 Jun 2019 22:37:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727091AbfF1Mha (ORCPT ); Fri, 28 Jun 2019 08:37:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbfF1MhZ (ORCPT ); Fri, 28 Jun 2019 08:37:25 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C5146C059B9F; Fri, 28 Jun 2019 12:37:24 +0000 (UTC) Received: from steredhat.redhat.com (ovpn-117-102.ams2.redhat.com [10.36.117.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id CC67C5D98E; Fri, 28 Jun 2019 12:37:18 +0000 (UTC) From: Stefano Garzarella To: netdev@vger.kernel.org Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Stefan Hajnoczi , "Michael S. Tsirkin" , "David S. Miller" , Jason Wang , linux-kernel@vger.kernel.org Subject: [PATCH v2 3/3] vsock/virtio: fix flush of works during the .remove() Date: Fri, 28 Jun 2019 14:36:59 +0200 Message-Id: <20190628123659.139576-4-sgarzare@redhat.com> In-Reply-To: <20190628123659.139576-1-sgarzare@redhat.com> References: <20190628123659.139576-1-sgarzare@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 28 Jun 2019 12:37:24 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch moves the flush of works after vdev->config->del_vqs(vdev), because we need to be sure that no workers run before to free the 'vsock' object. Since we stopped the workers using the [tx|rx|event]_run flags, we are sure no one is accessing the device while we are calling vdev->config->reset(vdev), so we can safely move the workers' flush. Before the vdev->config->del_vqs(vdev), workers can be scheduled by VQ callbacks, so we must flush them after del_vqs(), to avoid use-after-free of 'vsock' object. Suggested-by: Michael S. Tsirkin Signed-off-by: Stefano Garzarella --- net/vmw_vsock/virtio_transport.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 1b44ec6f3f6c..96dafa978268 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -680,12 +680,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev) rcu_assign_pointer(the_virtio_vsock, NULL); synchronize_rcu(); - flush_work(&vsock->loopback_work); - flush_work(&vsock->rx_work); - flush_work(&vsock->tx_work); - flush_work(&vsock->event_work); - flush_work(&vsock->send_pkt_work); - /* Reset all connected sockets when the device disappear */ vsock_for_each_connected_socket(virtio_vsock_reset_sock); @@ -740,6 +734,15 @@ static void virtio_vsock_remove(struct virtio_device *vdev) /* Delete virtqueues and flush outstanding callbacks if any */ vdev->config->del_vqs(vdev); + /* Other works can be queued before 'config->del_vqs()', so we flush + * all works before to free the vsock object to avoid use after free. + */ + flush_work(&vsock->loopback_work); + flush_work(&vsock->rx_work); + flush_work(&vsock->tx_work); + flush_work(&vsock->event_work); + flush_work(&vsock->send_pkt_work); + mutex_unlock(&the_virtio_vsock_mutex); kfree(vsock);