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Date:   Wed, 17 Oct 2018 22:30:01 -0700 (PDT)
Message-Id: <20181017.223001.1576138840071012489.davem@davemloft.net>
To:     ake@igel.co.jp
Cc:     jasowang@redhat.com, mst@redhat.com,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] virtio_net: avoid using netif_tx_disable() for
 serializing tx routine
From:   David Miller <davem@davemloft.net>
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        <20181017104419.13003-1-ake@igel.co.jp>
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From: Ake Koomsin <ake@igel.co.jp>
Date: Wed, 17 Oct 2018 19:44:12 +0900

> Commit 713a98d90c5e ("virtio-net: serialize tx routine during reset")
> introduces netif_tx_disable() after netif_device_detach() in order to
> avoid use-after-free of tx queues. However, there are two issues.
> 
> 1) Its operation is redundant with netif_device_detach() in case the
>    interface is running.
> 2) In case of the interface is not running before suspending and
>    resuming, the tx does not get resumed by netif_device_attach().
>    This results in losing network connectivity.
> 
> It is better to use netif_tx_lock_bh()/netif_tx_unlock_bh() instead for
> serializing tx routine during reset. This also preserves the symmetry
> of netif_device_detach() and netif_device_attach().
> 
> Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during reset")
> Signed-off-by: Ake Koomsin <ake@igel.co.jp>

Applied and queued up for -stable.