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. Signed-off-by: Jason Wang <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
