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| author | Jason Wang <jasowang@redhat.com> | 2013-05-28 18:32:11 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-05-29 00:21:32 -0700 |
| commit | 8e6d91ae0917bf934ed86411148f79d904728d51 (patch) | |
| tree | ccffbffdcb079b492082a8e8f0b73b446b238d8c | |
| parent | 456db6a4d495f40777da6f1f32f62f13026f52db (diff) | |
| download | linux-8e6d91ae0917bf934ed86411148f79d904728d51.tar.gz | |
tuntap: forbid changing mq flag for persistent device
We currently allow changing the mq flag (IFF_MULTI_QUEUE) for a persistent device. This will result a mismatch between the number the queues in netdev and tuntap. This is because we only allocate a 1q netdevice when IFF_MULTI_QUEUE was not specified, so when we set the IFF_MULTI_QUEUE and try to attach more queues later, netif_set_real_num_tx_queues() may fail which result a single queue netdevice with multiple sockets attached. Solve this by disallowing changing the mq flag for persistent device. Bug was introduced by commit edfb6a148ce62e5e19354a1dcd9a34e00815c2a1 (tuntap: reduce memory using of queues). Reported-by: Sriram Narasimhan <sriram.narasimhan@hp.com> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/tun.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index f042b0373e5d..89776c592151 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1585,6 +1585,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) else return -EINVAL; + if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != + !!(tun->flags & TUN_TAP_MQ)) + return -EINVAL; + if (tun_not_capable(tun)) return -EPERM; err = security_tun_dev_open(tun->security); |