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Commit 545a8e79 authored by stephen hemminger's avatar stephen hemminger Committed by David S. Miller
Browse files

netvsc: use RCU to protect inner device structure 



The netvsc driver has an internal structure (netvsc_device) which
is created when device is opened and released when device is closed.
And also opened/released when MTU or number of channels change.

Since this is referenced in the receive and transmit path, it is
safer to use RCU to protect/prevent use after free problems.

Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3071ada4

drivers/net/hyperv/hyperv_net.h

+3 −1
Original line number Diff line number Diff line
@@ -686,7 +686,7 @@ struct net_device_context { 
	/* point back to our device context */

	struct hv_device *device_ctx;

	/* netvsc_device */

	struct netvsc_device *nvdev;

	struct netvsc_device __rcu *nvdev;

	/* reconfigure work */

	struct delayed_work dwork;

	/* last reconfig time */
@@ -780,6 +780,8 @@ struct netvsc_device { 
	atomic_t open_cnt;



	struct netvsc_channel chan_table[VRSS_CHANNEL_MAX];



	struct rcu_head rcu;

};



static inline struct netvsc_device *

drivers/net/hyperv/netvsc.c

+11 −5
Original line number Diff line number Diff line
@@ -80,8 +80,10 @@ static struct netvsc_device *alloc_net_device(void) 
	return net_device;

}



static void free_netvsc_device(struct netvsc_device *nvdev)

static void free_netvsc_device(struct rcu_head *head)

{

	struct netvsc_device *nvdev

		= container_of(head, struct netvsc_device, rcu);

	int i;



	for (i = 0; i < VRSS_CHANNEL_MAX; i++)
@@ -90,6 +92,10 @@ static void free_netvsc_device(struct netvsc_device *nvdev) 
	kfree(nvdev);

}



static void free_netvsc_device_rcu(struct netvsc_device *nvdev)

{

	call_rcu(&nvdev->rcu, free_netvsc_device);

}



static struct netvsc_device *get_outbound_net_device(struct hv_device *device)

{
@@ -551,7 +557,7 @@ void netvsc_device_remove(struct hv_device *device) 


	netvsc_disconnect_vsp(device);



	net_device_ctx->nvdev = NULL;

	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);



	/*

	 * At this point, no one should be accessing net_device
@@ -566,7 +572,7 @@ void netvsc_device_remove(struct hv_device *device) 
		napi_disable(&net_device->chan_table[i].napi);



	/* Release all resources */

	free_netvsc_device(net_device);

	free_netvsc_device_rcu(net_device);

}



#define RING_AVAIL_PERCENT_HIWATER 20
@@ -1322,7 +1328,7 @@ int netvsc_device_add(struct hv_device *device, 
	 */

	wmb();



	net_device_ctx->nvdev = net_device;

	rcu_assign_pointer(net_device_ctx->nvdev, net_device);



	/* Connect with the NetVsp */

	ret = netvsc_connect_vsp(device);
@@ -1341,7 +1347,7 @@ int netvsc_device_add(struct hv_device *device, 
	vmbus_close(device->channel);



cleanup:

	free_netvsc_device(net_device);

	free_netvsc_device(&net_device->rcu);



	return ret;

}

drivers/net/hyperv/netvsc_drv.c

+43 −18
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static void do_set_multicast(struct work_struct *w) 
		container_of(w, struct net_device_context, work);

	struct hv_device *device_obj = ndevctx->device_ctx;

	struct net_device *ndev = hv_get_drvdata(device_obj);

	struct netvsc_device *nvdev = ndevctx->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndevctx->nvdev);

	struct rndis_device *rdev;



	if (!nvdev)
@@ -116,7 +116,7 @@ static int netvsc_open(struct net_device *net) 
static int netvsc_close(struct net_device *net)

{

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct netvsc_device *nvdev = net_device_ctx->nvdev;

	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);

	int ret;

	u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;

	struct vmbus_channel *chn;
@@ -637,9 +637,9 @@ int netvsc_recv_callback(struct net_device *net, 
			 const struct ndis_pkt_8021q_info *vlan)

{

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct netvsc_device *net_device = net_device_ctx->nvdev;

	struct netvsc_device *net_device;

	u16 q_idx = channel->offermsg.offer.sub_channel_index;

	struct netvsc_channel *nvchan = &net_device->chan_table[q_idx];

	struct netvsc_channel *nvchan;

	struct net_device *vf_netdev;

	struct sk_buff *skb;

	struct netvsc_stats *rx_stats;
@@ -655,6 +655,11 @@ int netvsc_recv_callback(struct net_device *net, 
	 * interface in the guest.

	 */

	rcu_read_lock();

	net_device = rcu_dereference(net_device_ctx->nvdev);

	if (unlikely(!net_device))

		goto drop;



	nvchan = &net_device->chan_table[q_idx];

	vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);

	if (vf_netdev && (vf_netdev->flags & IFF_UP))

		net = vf_netdev;
@@ -663,6 +668,7 @@ int netvsc_recv_callback(struct net_device *net, 
	skb = netvsc_alloc_recv_skb(net, &nvchan->napi,

				    csum_info, vlan, data, len);

	if (unlikely(!skb)) {

drop:

		++net->stats.rx_dropped;

		rcu_read_unlock();

		return NVSP_STAT_FAIL;
@@ -704,7 +710,7 @@ static void netvsc_get_channels(struct net_device *net, 
				struct ethtool_channels *channel)

{

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct netvsc_device *nvdev = net_device_ctx->nvdev;

	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);



	if (nvdev) {

		channel->max_combined	= nvdev->max_chn;
@@ -741,7 +747,7 @@ static int netvsc_set_channels(struct net_device *net, 
{

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct hv_device *dev = net_device_ctx->device_ctx;

	struct netvsc_device *nvdev = net_device_ctx->nvdev;

	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);

	unsigned int count = channels->combined_count;

	bool was_running;

	int ret;
@@ -848,7 +854,7 @@ static int netvsc_set_link_ksettings(struct net_device *dev, 
static int netvsc_change_mtu(struct net_device *ndev, int mtu)

{

	struct net_device_context *ndevctx = netdev_priv(ndev);

	struct netvsc_device *nvdev = ndevctx->nvdev;

	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);

	struct hv_device *hdev = ndevctx->device_ctx;

	struct netvsc_device_info device_info;

	bool was_running;
@@ -897,7 +903,7 @@ static void netvsc_get_stats64(struct net_device *net, 
			       struct rtnl_link_stats64 *t)

{

	struct net_device_context *ndev_ctx = netdev_priv(net);

	struct netvsc_device *nvdev = ndev_ctx->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndev_ctx->nvdev);

	int i;



	if (!nvdev)
@@ -982,7 +988,10 @@ static const struct { 
static int netvsc_get_sset_count(struct net_device *dev, int string_set)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *nvdev = ndc->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);



	if (!nvdev)

		return -ENODEV;



	switch (string_set) {

	case ETH_SS_STATS:
@@ -996,13 +1005,16 @@ static void netvsc_get_ethtool_stats(struct net_device *dev, 
				     struct ethtool_stats *stats, u64 *data)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *nvdev = ndc->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);

	const void *nds = &ndc->eth_stats;

	const struct netvsc_stats *qstats;

	unsigned int start;

	u64 packets, bytes;

	int i, j;



	if (!nvdev)

		return;



	for (i = 0; i < NETVSC_GLOBAL_STATS_LEN; i++)

		data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);
@@ -1031,10 +1043,13 @@ static void netvsc_get_ethtool_stats(struct net_device *dev, 
static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *nvdev = ndc->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);

	u8 *p = data;

	int i;



	if (!nvdev)

		return;



	switch (stringset) {

	case ETH_SS_STATS:

		for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
@@ -1086,7 +1101,10 @@ netvsc_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info, 
		 u32 *rules)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *nvdev = ndc->nvdev;

	struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);



	if (!nvdev)

		return -ENODEV;



	switch (info->cmd) {

	case ETHTOOL_GRXRINGS:
@@ -1122,10 +1140,13 @@ static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, 
			   u8 *hfunc)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *ndev = ndc->nvdev;

	struct netvsc_device *ndev = rcu_dereference(ndc->nvdev);

	struct rndis_device *rndis_dev = ndev->extension;

	int i;



	if (!ndev)

		return -ENODEV;



	if (hfunc)

		*hfunc = ETH_RSS_HASH_TOP;	/* Toeplitz */
@@ -1144,10 +1165,13 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir, 
			   const u8 *key, const u8 hfunc)

{

	struct net_device_context *ndc = netdev_priv(dev);

	struct netvsc_device *ndev = ndc->nvdev;

	struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);

	struct rndis_device *rndis_dev = ndev->extension;

	int i;



	if (!ndev)

		return -ENODEV;



	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)

		return -EOPNOTSUPP;
@@ -1224,7 +1248,7 @@ static void netvsc_link_change(struct work_struct *w) 
	if (ndev_ctx->start_remove)

		goto out_unlock;



	net_device = ndev_ctx->nvdev;

	net_device = rtnl_dereference(ndev_ctx->nvdev);

	rdev = net_device->extension;



	next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
@@ -1365,7 +1389,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev) 
		return NOTIFY_DONE;



	net_device_ctx = netdev_priv(ndev);

	netvsc_dev = net_device_ctx->nvdev;

	netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);

	if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))

		return NOTIFY_DONE;
@@ -1391,7 +1415,7 @@ static int netvsc_vf_up(struct net_device *vf_netdev) 
		return NOTIFY_DONE;



	net_device_ctx = netdev_priv(ndev);

	netvsc_dev = net_device_ctx->nvdev;

	netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);



	netdev_info(ndev, "VF up: %s\n", vf_netdev->name);
@@ -1425,7 +1449,7 @@ static int netvsc_vf_down(struct net_device *vf_netdev) 
		return NOTIFY_DONE;



	net_device_ctx = netdev_priv(ndev);

	netvsc_dev = net_device_ctx->nvdev;

	netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);



	netdev_info(ndev, "VF down: %s\n", vf_netdev->name);

	netvsc_switch_datapath(ndev, false);
@@ -1519,6 +1543,7 @@ static int netvsc_probe(struct hv_device *dev, 
		NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;

	net->vlan_features = net->features;



	/* RCU not necessary here, device not registered */

	nvdev = net_device_ctx->nvdev;

	netif_set_real_num_tx_queues(net, nvdev->num_chn);

	netif_set_real_num_rx_queues(net, nvdev->num_chn);