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: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger
David S. Miller
parent
3071ada491
commit
545a8e79bd
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@ -686,7 +686,7 @@ struct net_device_context {
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/* point back to our device context */
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struct hv_device *device_ctx;
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/* netvsc_device */
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struct netvsc_device *nvdev;
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struct netvsc_device __rcu *nvdev;
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/* reconfigure work */
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struct delayed_work dwork;
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/* last reconfig time */
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@ -780,6 +780,8 @@ struct netvsc_device {
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atomic_t open_cnt;
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struct netvsc_channel chan_table[VRSS_CHANNEL_MAX];
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struct rcu_head rcu;
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};
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static inline struct netvsc_device *
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@ -80,8 +80,10 @@ static struct netvsc_device *alloc_net_device(void)
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return net_device;
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}
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static void free_netvsc_device(struct netvsc_device *nvdev)
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static void free_netvsc_device(struct rcu_head *head)
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{
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struct netvsc_device *nvdev
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= container_of(head, struct netvsc_device, rcu);
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int i;
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for (i = 0; i < VRSS_CHANNEL_MAX; i++)
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@ -90,6 +92,10 @@ static void free_netvsc_device(struct netvsc_device *nvdev)
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kfree(nvdev);
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}
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static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
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{
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call_rcu(&nvdev->rcu, free_netvsc_device);
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}
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static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
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{
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@ -551,7 +557,7 @@ void netvsc_device_remove(struct hv_device *device)
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netvsc_disconnect_vsp(device);
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net_device_ctx->nvdev = NULL;
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RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
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/*
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* At this point, no one should be accessing net_device
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@ -566,7 +572,7 @@ void netvsc_device_remove(struct hv_device *device)
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napi_disable(&net_device->chan_table[i].napi);
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/* Release all resources */
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free_netvsc_device(net_device);
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free_netvsc_device_rcu(net_device);
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}
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#define RING_AVAIL_PERCENT_HIWATER 20
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@ -1322,7 +1328,7 @@ int netvsc_device_add(struct hv_device *device,
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*/
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wmb();
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net_device_ctx->nvdev = net_device;
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rcu_assign_pointer(net_device_ctx->nvdev, net_device);
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/* Connect with the NetVsp */
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ret = netvsc_connect_vsp(device);
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@ -1341,7 +1347,7 @@ close:
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vmbus_close(device->channel);
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cleanup:
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free_netvsc_device(net_device);
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free_netvsc_device(&net_device->rcu);
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return ret;
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}
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@ -62,7 +62,7 @@ static void do_set_multicast(struct work_struct *w)
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container_of(w, struct net_device_context, work);
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struct hv_device *device_obj = ndevctx->device_ctx;
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struct net_device *ndev = hv_get_drvdata(device_obj);
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struct netvsc_device *nvdev = ndevctx->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndevctx->nvdev);
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struct rndis_device *rdev;
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if (!nvdev)
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@ -116,7 +116,7 @@ static int netvsc_open(struct net_device *net)
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static int netvsc_close(struct net_device *net)
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{
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struct net_device_context *net_device_ctx = netdev_priv(net);
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struct netvsc_device *nvdev = net_device_ctx->nvdev;
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struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
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int ret;
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u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;
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struct vmbus_channel *chn;
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@ -637,9 +637,9 @@ int netvsc_recv_callback(struct net_device *net,
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const struct ndis_pkt_8021q_info *vlan)
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{
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struct net_device_context *net_device_ctx = netdev_priv(net);
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struct netvsc_device *net_device = net_device_ctx->nvdev;
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struct netvsc_device *net_device;
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u16 q_idx = channel->offermsg.offer.sub_channel_index;
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struct netvsc_channel *nvchan = &net_device->chan_table[q_idx];
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struct netvsc_channel *nvchan;
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struct net_device *vf_netdev;
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struct sk_buff *skb;
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struct netvsc_stats *rx_stats;
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@ -655,6 +655,11 @@ int netvsc_recv_callback(struct net_device *net,
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* interface in the guest.
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*/
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rcu_read_lock();
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net_device = rcu_dereference(net_device_ctx->nvdev);
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if (unlikely(!net_device))
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goto drop;
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nvchan = &net_device->chan_table[q_idx];
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vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);
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if (vf_netdev && (vf_netdev->flags & IFF_UP))
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net = vf_netdev;
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@ -663,6 +668,7 @@ int netvsc_recv_callback(struct net_device *net,
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skb = netvsc_alloc_recv_skb(net, &nvchan->napi,
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csum_info, vlan, data, len);
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if (unlikely(!skb)) {
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drop:
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++net->stats.rx_dropped;
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rcu_read_unlock();
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return NVSP_STAT_FAIL;
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@ -704,7 +710,7 @@ static void netvsc_get_channels(struct net_device *net,
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struct ethtool_channels *channel)
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{
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struct net_device_context *net_device_ctx = netdev_priv(net);
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struct netvsc_device *nvdev = net_device_ctx->nvdev;
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struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
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if (nvdev) {
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channel->max_combined = nvdev->max_chn;
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@ -741,7 +747,7 @@ static int netvsc_set_channels(struct net_device *net,
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{
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struct net_device_context *net_device_ctx = netdev_priv(net);
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struct hv_device *dev = net_device_ctx->device_ctx;
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struct netvsc_device *nvdev = net_device_ctx->nvdev;
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struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
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unsigned int count = channels->combined_count;
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bool was_running;
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int ret;
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@ -848,7 +854,7 @@ static int netvsc_set_link_ksettings(struct net_device *dev,
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static int netvsc_change_mtu(struct net_device *ndev, int mtu)
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{
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struct net_device_context *ndevctx = netdev_priv(ndev);
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struct netvsc_device *nvdev = ndevctx->nvdev;
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struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
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struct hv_device *hdev = ndevctx->device_ctx;
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struct netvsc_device_info device_info;
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bool was_running;
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@ -897,7 +903,7 @@ static void netvsc_get_stats64(struct net_device *net,
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struct rtnl_link_stats64 *t)
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{
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struct net_device_context *ndev_ctx = netdev_priv(net);
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struct netvsc_device *nvdev = ndev_ctx->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndev_ctx->nvdev);
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int i;
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if (!nvdev)
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@ -982,7 +988,10 @@ static const struct {
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static int netvsc_get_sset_count(struct net_device *dev, int string_set)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *nvdev = ndc->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
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if (!nvdev)
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return -ENODEV;
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switch (string_set) {
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case ETH_SS_STATS:
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@ -996,13 +1005,16 @@ static void netvsc_get_ethtool_stats(struct net_device *dev,
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struct ethtool_stats *stats, u64 *data)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *nvdev = ndc->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
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const void *nds = &ndc->eth_stats;
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const struct netvsc_stats *qstats;
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unsigned int start;
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u64 packets, bytes;
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int i, j;
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if (!nvdev)
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return;
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for (i = 0; i < NETVSC_GLOBAL_STATS_LEN; i++)
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data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);
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@ -1031,10 +1043,13 @@ static void netvsc_get_ethtool_stats(struct net_device *dev,
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static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *nvdev = ndc->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
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u8 *p = data;
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int i;
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if (!nvdev)
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return;
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switch (stringset) {
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case ETH_SS_STATS:
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for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
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@ -1086,7 +1101,10 @@ netvsc_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info,
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u32 *rules)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *nvdev = ndc->nvdev;
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struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
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if (!nvdev)
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return -ENODEV;
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switch (info->cmd) {
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case ETHTOOL_GRXRINGS:
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@ -1122,10 +1140,13 @@ static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
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u8 *hfunc)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *ndev = ndc->nvdev;
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struct netvsc_device *ndev = rcu_dereference(ndc->nvdev);
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struct rndis_device *rndis_dev = ndev->extension;
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int i;
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if (!ndev)
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return -ENODEV;
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if (hfunc)
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*hfunc = ETH_RSS_HASH_TOP; /* Toeplitz */
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@ -1144,10 +1165,13 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
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const u8 *key, const u8 hfunc)
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{
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struct net_device_context *ndc = netdev_priv(dev);
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struct netvsc_device *ndev = ndc->nvdev;
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struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);
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struct rndis_device *rndis_dev = ndev->extension;
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int i;
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if (!ndev)
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return -ENODEV;
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if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
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return -EOPNOTSUPP;
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@ -1224,7 +1248,7 @@ static void netvsc_link_change(struct work_struct *w)
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if (ndev_ctx->start_remove)
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goto out_unlock;
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net_device = ndev_ctx->nvdev;
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net_device = rtnl_dereference(ndev_ctx->nvdev);
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rdev = net_device->extension;
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next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
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@ -1365,7 +1389,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev)
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return NOTIFY_DONE;
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net_device_ctx = netdev_priv(ndev);
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netvsc_dev = net_device_ctx->nvdev;
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netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
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if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))
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return NOTIFY_DONE;
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@ -1391,7 +1415,7 @@ static int netvsc_vf_up(struct net_device *vf_netdev)
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return NOTIFY_DONE;
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net_device_ctx = netdev_priv(ndev);
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netvsc_dev = net_device_ctx->nvdev;
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netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
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netdev_info(ndev, "VF up: %s\n", vf_netdev->name);
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@ -1425,7 +1449,7 @@ static int netvsc_vf_down(struct net_device *vf_netdev)
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return NOTIFY_DONE;
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net_device_ctx = netdev_priv(ndev);
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netvsc_dev = net_device_ctx->nvdev;
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netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
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netdev_info(ndev, "VF down: %s\n", vf_netdev->name);
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netvsc_switch_datapath(ndev, false);
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@ -1519,6 +1543,7 @@ static int netvsc_probe(struct hv_device *dev,
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NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;
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net->vlan_features = net->features;
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/* RCU not necessary here, device not registered */
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nvdev = net_device_ctx->nvdev;
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netif_set_real_num_tx_queues(net, nvdev->num_chn);
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netif_set_real_num_rx_queues(net, nvdev->num_chn);
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