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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	netdev@vger.kernel.org,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
	"Daniel Borkmann" <borkmann@iogearbox.net>,
	"David S. Miller" <davem@davemloft.net>,
	brouer@redhat.com, "Björn Töpel" <bjorn.topel@intel.com>,
	"Karlsson, Magnus" <magnus.karlsson@intel.com>
Subject: Re: [RFC net PATCH] virtio_net: disable XDP_REDIRECT in receive_mergeable() case
Date: Sun, 18 Feb 2018 15:22:04 +0100	[thread overview]
Message-ID: <20180218152204.671c21a8@redhat.com> (raw)
In-Reply-To: <25a9b6f0-e3f4-30b7-054a-d8e58d80cfcd@redhat.com>

On Fri, 16 Feb 2018 13:31:37 +0800 Jason Wang <jasowang@redhat.com> wrote:

> > Besides the described bug:
> >
> > Update(1): There is also a OOM leak in the XDP_REDIRECT code, which
> > receive_small() is likely also affected by.

Found the issue behind this memory leak... page refcnt issues when
hitting xmit error paths.

> > Update(2): Also observed a guest crash when redirecting out an
> > another virtio_net device, when device is down.  

Also found reason behind this. It is not related to a "down" device.
It caused by redirect into a virtio_net device that does not have setup
sufficient XDP TX queues (which it assumes is one per CPU). I have a
preliminary fix patch.

> Will have a look at these issues. (Holiday in china now, so will do it 
> after).

No worry.  I can take care of this... I'll cleanup my patches and test
them Monday, should have patches ready Tuesday... as I want to make
sure they work in all the different error cases.

I'll be working on improvements for the XDP_REDIRECT code paths anyway
next week... in preparations for supporting the AF_XDP use case.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

  parent reply	other threads:[~2018-02-18 14:22 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-15 22:43 [RFC net PATCH] virtio_net: disable XDP_REDIRECT in receive_mergeable() case Jesper Dangaard Brouer
2018-02-16  5:31 ` Jason Wang
2018-02-16 15:41   ` Jesper Dangaard Brouer
2018-02-16 17:19     ` John Fastabend
2018-02-20 11:17       ` Jesper Dangaard Brouer
2018-02-20 16:52         ` John Fastabend
2018-02-22  5:50           ` Jason Wang
2018-02-22  3:25     ` Jason Wang
2018-02-26 20:16     ` Michael S. Tsirkin
2018-02-18 14:22   ` Jesper Dangaard Brouer [this message]
2018-02-26 20:16 ` Michael S. Tsirkin

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