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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 A2065C4161D for ; Thu, 11 Oct 2018 13:06:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E6252085B for ; Thu, 11 Oct 2018 13:06:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E6252085B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1728149AbeJKUdc (ORCPT ); Thu, 11 Oct 2018 16:33:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54232 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726135AbeJKUdc (ORCPT ); Thu, 11 Oct 2018 16:33:32 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D11DF3D96B; Thu, 11 Oct 2018 13:06:24 +0000 (UTC) Received: from [10.72.12.114] (ovpn-12-114.pek2.redhat.com [10.72.12.114]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A330C65F6C; Thu, 11 Oct 2018 13:06:20 +0000 (UTC) Subject: Re: [PATCH] virtio_net: enable tx after resuming from suspend To: ake Cc: "Michael S. Tsirkin" , "David S. Miller" , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20181011075127.2608-1-ake@igel.co.jp> <7e87b140-79ae-c79e-40ed-dc76b38eeae4@igel.co.jp> From: Jason Wang Message-ID: Date: Thu, 11 Oct 2018 21:06:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <7e87b140-79ae-c79e-40ed-dc76b38eeae4@igel.co.jp> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 11 Oct 2018 13:06:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年10月11日 18:22, ake wrote: > > On 2018年10月11日 18:44, Jason Wang wrote: >> >> On 2018年10月11日 15:51, Ake Koomsin wrote: >>> commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") >>> disabled the virtio tx before going to suspend to avoid a use after free. >>> However, after resuming, it causes the virtio_net device to lose its >>> network connectivity. >>> >>> To solve the issue, we need to enable tx after resuming. >>> >>> Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during >>> reset") >>> Signed-off-by: Ake Koomsin >>> --- >>>   drivers/net/virtio_net.c | 1 + >>>   1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >>> index dab504ec5e50..3453d80f5f81 100644 >>> --- a/drivers/net/virtio_net.c >>> +++ b/drivers/net/virtio_net.c >>> @@ -2256,6 +2256,7 @@ static int virtnet_restore_up(struct >>> virtio_device *vdev) >>>       } >>>         netif_device_attach(vi->dev); >>> +    netif_start_queue(vi->dev); >> I believe this is duplicated with netif_tx_wake_all_queues() in >> netif_device_attach() above? > Thank you for your review. > > If both netif_tx_wake_all_queues() and netif_start_queue() result in > clearing __QUEUE_STATE_DRV_XOFF, then is it possible that some > conditions in netif_device_attach() is not satisfied? Yes, maybe. One case I can see now is when the device is down, in this case netif_device_attach() won't try to wakeup the queue. > Without > netif_start_queue(), the virtio_net device does not resume properly > after waking up. How do you trigger the issue? Just do suspend/resume? > > Is it better to report this as a bug first? Nope, you're very welcome to post patch directly. > If I am to do more > investigation, what areas should I look into? As you've figured out, you can start with why netif_tx_wake_all_queues() were not executed? (Btw, does the issue disappear if you move netif_tx_disable() under the check of netif_running() in virtnet_freeze_down()?) Thanks > > Best Regards > Ake Koomsin >