Messages in this thread Patch in this message | | | From | Jason Wang <> | Subject | [net-next PATCH 1/8] macvtap: fix a possible race between queue selection and changing queues | Date | Thu, 6 Jun 2013 17:54:33 +0800 |
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Complier may generate codes that re-read the vlan->numvtaps during macvtap_get_queue(). This may lead a race if vlan->numvtaps were changed in the same time and which 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 vlan->numvtaps were only read once.
Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/macvtap.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 68efb91..5e485e3 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -172,7 +172,7 @@ static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, { struct macvlan_dev *vlan = netdev_priv(dev); struct macvtap_queue *tap = NULL; - int numvtaps = vlan->numvtaps; + int numvtaps = ACCESS_ONCE(vlan->numvtaps); __u32 rxq; if (!numvtaps) -- 1.7.1
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