From: David Miller <davem@davemloft.net>
To: lifei.shirley@bytedance.com
Cc: jasowang@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, zhengfeiran@bytedance.com,
duanxiongchun@bytedance.com
Subject: Re: [PATCH net v2] tun: wake up waitqueues after IFF_UP is set
Date: Tue, 18 Jun 2019 10:55:48 -0700 (PDT) [thread overview]
Message-ID: <20190618.105548.2200622033433520074.davem@davemloft.net> (raw)
In-Reply-To: <20190617132636.72496-1-lifei.shirley@bytedance.com>
From: Fei Li <lifei.shirley@bytedance.com>
Date: Mon, 17 Jun 2019 21:26:36 +0800
> Currently after setting tap0 link up, the tun code wakes tx/rx waited
> queues up in tun_net_open() when .ndo_open() is called, however the
> IFF_UP flag has not been set yet. If there's already a wait queue, it
> would fail to transmit when checking the IFF_UP flag in tun_sendmsg().
> Then the saving vhost_poll_start() will add the wq into wqh until it
> is waken up again. Although this works when IFF_UP flag has been set
> when tun_chr_poll detects; this is not true if IFF_UP flag has not
> been set at that time. Sadly the latter case is a fatal error, as
> the wq will never be waken up in future unless later manually
> setting link up on purpose.
>
> Fix this by moving the wakeup process into the NETDEV_UP event
> notifying process, this makes sure IFF_UP has been set before all
> waited queues been waken up.
>
> Signed-off-by: Fei Li <lifei.shirley@bytedance.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
Applied and queued up for -stable, thanks.
next prev parent reply other threads:[~2019-06-18 17:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 13:26 [PATCH net v2] tun: wake up waitqueues after IFF_UP is set Fei Li
2019-06-18 17:55 ` David Miller [this message]
2019-06-19 16:02 ` [External Email] " 李菲
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