From: Jason Wang <jasowang@redhat.com>
To: ake <ake@igel.co.jp>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] virtio_net: enable tx after resuming from suspend
Date: Thu, 11 Oct 2018 21:06:18 +0800 [thread overview]
Message-ID: <a156fd7e-e36e-e4e9-c240-3117ecc5b1b4@redhat.com> (raw)
In-Reply-To: <7e87b140-79ae-c79e-40ed-dc76b38eeae4@igel.co.jp>
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 <ake@igel.co.jp>
>>> ---
>>> 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
>
next prev parent reply other threads:[~2018-10-11 13:06 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 7:51 [PATCH] virtio_net: enable tx after resuming from suspend Ake Koomsin
2018-10-11 9:44 ` Jason Wang
2018-10-11 10:22 ` ake
2018-10-11 13:06 ` Jason Wang [this message]
2018-10-12 4:30 ` ake
2018-10-12 8:23 ` Jason Wang
2018-10-12 9:18 ` ake
2018-10-15 10:08 ` ake
2018-10-16 8:53 ` Jason Wang
2018-10-16 10:15 ` ake
2018-10-17 6:18 ` Jason Wang
2018-10-17 7:59 ` [PATCH v2] virtio_net: avoid using netif_tx_disable() for serializing tx routine Ake Koomsin
2018-10-17 9:02 ` Jason Wang
2018-10-17 10:44 ` [PATCH v3] " Ake Koomsin
2018-10-17 12:30 ` Jason Wang
2018-10-17 15:09 ` Michael S. Tsirkin
2018-10-18 3:25 ` ake
2018-10-18 5:30 ` David Miller
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