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hv_netvsc: use start_remove flag to protect netvsc_link_change() 

netvsc_link_change() can race with netvsc_change_mtu() or
netvsc_set_channels() as these functions destroy struct netvsc_device and
rndis filter. Use start_remove flag for syncronization. As
netvsc_change_mtu()/netvsc_set_channels() are called with rtnl lock held
we need to take it before checking start_remove value in
netvsc_link_change().

Reported-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vitaly Kuznetsov 2016-05-13 13:55:21 +02:00 committed by David S. Miller
parent f580aec4bf
commit 1bdcec8a5f
1 changed files with 17 additions and 4 deletions
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21
drivers/net/hyperv/netvsc_drv.c
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@ -838,6 +838,8 @@ static int netvsc_set_channels(struct net_device *net,
out:
netvsc_open(net);
net_device_ctx->start_remove = false;
/* We may have missed link change notifications */
schedule_delayed_work(&net_device_ctx->dwork, 0);
return ret;
@ -946,6 +948,9 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
netvsc_open(ndev);
ndevctx->start_remove = false;
/* We may have missed link change notifications */
schedule_delayed_work(&ndevctx->dwork, 0);
return ret;
}
@ -1066,6 +1071,11 @@ static void netvsc_link_change(struct work_struct *w)
unsigned long flags, next_reconfig, delay;
ndev_ctx = container_of(w, struct net_device_context, dwork.work);
rtnl_lock();
if (ndev_ctx->start_remove)
goto out_unlock;
net_device = hv_get_drvdata(ndev_ctx->device_ctx);
rdev = net_device->extension;
net = net_device->ndev;
@ -1079,7 +1089,7 @@ static void netvsc_link_change(struct work_struct *w)
delay = next_reconfig - jiffies;
delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
schedule_delayed_work(&ndev_ctx->dwork, delay);
return;
goto out_unlock;
}
ndev_ctx->last_reconfig = jiffies;
@ -1093,9 +1103,7 @@ static void netvsc_link_change(struct work_struct *w)
spin_unlock_irqrestore(&ndev_ctx->lock, flags);
if (!event)
return;
rtnl_lock();
goto out_unlock;
switch (event->event) {
/* Only the following events are possible due to the check in
@ -1144,6 +1152,11 @@ static void netvsc_link_change(struct work_struct *w)
*/
if (reschedule)
schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);
return;
out_unlock:
rtnl_unlock();
}
static void netvsc_free_netdev(struct net_device *netdev)