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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 96C9CC54E4B for ; Tue, 12 May 2020 03:27:18 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 58F0D206B7 for ; Tue, 12 May 2020 03:27:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="i/0hwGqb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58F0D206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34116 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jYLZd-0002Jr-Gc for qemu-devel@archiver.kernel.org; Mon, 11 May 2020 23:27:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57352) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYLYw-0001oJ-Ru for qemu-devel@nongnu.org; Mon, 11 May 2020 23:26:34 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:56990 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jYLYw-0006qk-58 for qemu-devel@nongnu.org; Mon, 11 May 2020 23:26:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589253990; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DjGoG6HYvQ7Xh17Dbq7k08Yb0uGrDYXsb6463Yi0c6Q=; b=i/0hwGqbF2DKHpBcHZ2N13AkFs00zG1M+fjuGW/0BNQ6YNTHly3RW1pb2BV3H3lcrQCitC hf5MPeIVUWOZhcNAmxYnGKvV5Lfr7WmEBzoUx6VdEjx/Rjjpfz77Jfw10u2EP6f4VcC07c jHN/cx83bgMEI4mxziGUGHIKcKGFCOM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-256-pw9mWlpGMzWNt224hs8YsA-1; Mon, 11 May 2020 23:26:28 -0400 X-MC-Unique: pw9mWlpGMzWNt224hs8YsA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7367D8014D7; Tue, 12 May 2020 03:26:26 +0000 (UTC) Received: from [10.72.13.96] (ovpn-13-96.pek2.redhat.com [10.72.13.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id 823375C1B5; Tue, 12 May 2020 03:26:13 +0000 (UTC) Subject: Re: [PATCH v2 4/5] vhost: check vring address before calling unmap To: Dima Stepanov References: <2d4952df2cc246f7421b4b9023a581b22210fc41.1588252862.git.dimastep@yandex-team.ru> <4a03e4aa-3a21-d678-be98-13268343b674@redhat.com> <20200511091117.GB27319@dimastep-nix> From: Jason Wang Message-ID: Date: Tue, 12 May 2020 11:26:11 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200511091117.GB27319@dimastep-nix> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/11 23:26:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, kwolf@redhat.com, yc-core@yandex-team.ru, qemu-block@nongnu.org, mst@redhat.com, qemu-devel@nongnu.org, dgilbert@redhat.com, arei.gonglei@huawei.com, raphael.norwitz@nutanix.com, fengli@smartx.com, stefanha@redhat.com, marcandre.lureau@redhat.com, pbonzini@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/5/11 下午5:11, Dima Stepanov wrote: > On Mon, May 11, 2020 at 11:05:58AM +0800, Jason Wang wrote: >> On 2020/4/30 下午9:36, Dima Stepanov wrote: >>> Since disconnect can happen at any time during initialization not all >>> vring buffers (for instance used vring) can be intialized successfully. >>> If the buffer was not initialized then vhost_memory_unmap call will lead >>> to SIGSEGV. Add checks for the vring address value before calling unmap. >>> Also add assert() in the vhost_memory_unmap() routine. >>> >>> Signed-off-by: Dima Stepanov >>> --- >>> hw/virtio/vhost.c | 27 +++++++++++++++++++++------ >>> 1 file changed, 21 insertions(+), 6 deletions(-) >>> >>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c >>> index ddbdc53..3ee50c4 100644 >>> --- a/hw/virtio/vhost.c >>> +++ b/hw/virtio/vhost.c >>> @@ -314,6 +314,8 @@ static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer, >>> hwaddr len, int is_write, >>> hwaddr access_len) >>> { >>> + assert(buffer); >>> + >>> if (!vhost_dev_has_iommu(dev)) { >>> cpu_physical_memory_unmap(buffer, len, is_write, access_len); >>> } >>> @@ -1132,12 +1134,25 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, >>> vhost_vq_index); >>> } >>> - vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx), >>> - 1, virtio_queue_get_used_size(vdev, idx)); >>> - vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx), >>> - 0, virtio_queue_get_avail_size(vdev, idx)); >>> - vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx), >>> - 0, virtio_queue_get_desc_size(vdev, idx)); >>> + /* >>> + * Since the vhost-user disconnect can happen during initialization >>> + * check if vring was initialized, before making unmap. >>> + */ >>> + if (vq->used) { >>> + vhost_memory_unmap(dev, vq->used, >>> + virtio_queue_get_used_size(vdev, idx), >>> + 1, virtio_queue_get_used_size(vdev, idx)); >>> + } >>> + if (vq->avail) { >>> + vhost_memory_unmap(dev, vq->avail, >>> + virtio_queue_get_avail_size(vdev, idx), >>> + 0, virtio_queue_get_avail_size(vdev, idx)); >>> + } >>> + if (vq->desc) { >>> + vhost_memory_unmap(dev, vq->desc, >>> + virtio_queue_get_desc_size(vdev, idx), >>> + 0, virtio_queue_get_desc_size(vdev, idx)); >>> + } >> >> Any reason not checking hdev->started instead? vhost_dev_start() will set it >> to true if virtqueues were correctly mapped. >> >> Thanks > Well i see it a little bit different: > - vhost_dev_start() sets hdev->started to true before starting > virtqueues > - vhost_virtqueue_start() maps all the memory > If we hit the vhost disconnect at the start of the > vhost_virtqueue_start(), for instance for this call: > r = dev->vhost_ops->vhost_set_vring_base(dev, &state); > Then we will call vhost_user_blk_disconnect: > vhost_user_blk_disconnect()-> > vhost_user_blk_stop()-> > vhost_dev_stop()-> > vhost_virtqueue_stop() > As a result we will come in this routine with the hdev->started still > set to true, but if used/avail/desc fields still uninitialized and set > to 0. I may miss something, but consider both vhost_dev_start() and vhost_user_blk_disconnect() were serialized in main loop. Can this really happen? Thanks > >> >>> } >>> static void vhost_eventfd_add(MemoryListener *listener,