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authorJason Wang <jasowang@redhat.com>2013-06-05 16:44:57 +0800
committerDavid S. Miller <davem@davemloft.net>2013-06-10 14:32:47 -0700
commit92bb73ea2c434618a68a58a2f3a5c3fd0b660d18 (patch)
tree3b310ab023ab438175bd2aa0ccf71814e3760ae9 /drivers/net
parent4364d5f96eed7994a2c625bd9216656e55fba0cb (diff)
tuntap: fix a possible race between queue selection and changing queues
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> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/tun.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 89776c59215..b1cbfbcff78 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -352,7 +352,7 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
u32 numqueues = 0;
rcu_read_lock();
- numqueues = tun->numqueues;
+ numqueues = ACCESS_ONCE(tun->numqueues);
txq = skb_get_rxhash(skb);
if (txq) {