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authorJason Wang <jasowang@redhat.com>2013-06-06 03:54:33 +0400
committerDavid S. Miller <davem@davemloft.net>2013-06-08 10:49:08 +0400
commited0483fa06e0efb86a82e382a00dbad02b62807c (patch)
tree2a0c920af1a2a7f748d81248cb027ca12f7f0bb5 /drivers/net/macvtap.c
parente403d295817cf9f8be3110eb7ee1a03981287495 (diff)
downloadlinux-ed0483fa06e0efb86a82e382a00dbad02b62807c.tar.xz
macvtap: fix a possible race between queue selection and changing queues
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> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/macvtap.c')
-rw-r--r--drivers/net/macvtap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 68efb91a5633..5e485e307424 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)