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Commit 1bdcec8a authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by David S. Miller
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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: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f580aec4

drivers/net/hyperv/netvsc_drv.c

+17 −4
Original line number Diff line number Diff line
@@ -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)