From: David Miller <davem@davemloft.net>
To: mst@redhat.com
Cc: jasowang@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tuntap: fix a possible race between queue selection and changing queues
Date: Mon, 10 Jun 2013 14:33:14 -0700 (PDT) [thread overview]
Message-ID: <20130610.143314.1237579707705274760.davem@davemloft.net> (raw)
In-Reply-To: <20130605103332.GD31830@redhat.com>
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Wed, 5 Jun 2013 13:33:32 +0300
> On Wed, Jun 05, 2013 at 04:44:57PM +0800, Jason Wang wrote:
>> Complier may generate codes that re-read the tun->numqueues during
>> tun_select_queue(). This may be a race if vlan->numqueues were changed in the
>> same time and can lead unexpected result (e.g. very huge value).
>>
>> We need prevent the compiler from generating such codes by adding an
>> ACCESS_ONCE() to make sure tun->numqueues were only read once.
>>
>> Bug were introduced by commit c8d68e6be1c3b242f1c598595830890b65cea64a
>> (tuntap: multiqueue support).
>>
>> Reported-by: Michael S. Tsirkin <mst@redhat.com>
>> Cc: Michael S. Tsirkin <mst@redhat.com>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
> This is a theoretical problem, right?
> So no need for stable.
Applied, thanks.
prev parent reply other threads:[~2013-06-10 21:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-05 8:44 [PATCH] tuntap: fix a possible race between queue selection and changing queues Jason Wang
2013-06-05 10:33 ` Michael S. Tsirkin
2013-06-10 21:33 ` David Miller [this message]
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