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Date: Wed, 22 Mar 2017 14:51:00 -0700
From: Stephen Hemminger <stephen@...workplumber.org>
To: kys@...rosoft.com, davem@...emloft.net
Cc: netdev@...r.kernel.org, haiyangz@...rosoft.com,
Stephen Hemminger <sthemmin@...rosoft.com>
Subject: [PATCH net-next 4/9] 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@...rosoft.com>
---
drivers/net/hyperv/hyperv_net.h | 4 ++-
drivers/net/hyperv/netvsc.c | 16 +++++++----
drivers/net/hyperv/netvsc_drv.c | 61 +++++++++++++++++++++++++++++------------
3 files changed, 57 insertions(+), 24 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index a33f2ee86044..0ade21f95d71 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -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 *
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 727762d0f13b..ab9118d620ab 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -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;
}
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 2f9de2e9f38e..d8a70d07eeec 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -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);
--
2.11.0
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