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authorCong Wang <xiyou.wangcong@gmail.com>2019-07-09 23:24:54 -0700
committerDavid S. Miller <davem@davemloft.net>2019-07-11 14:37:45 -0700
commit311633b604063a8a5d3fbc74d0565b42df721f68 (patch)
tree38c375bc8034c2539c0f2111d2d72df43a3fc83f /net
parentnet: stmmac: Fix misuses of GENMASK macro (diff)
downloadlinux-dev-311633b604063a8a5d3fbc74d0565b42df721f68.tar.xz
linux-dev-311633b604063a8a5d3fbc74d0565b42df721f68.zip
hsr: switch ->dellink() to ->ndo_uninit()
Switching from ->priv_destructor to dellink() has an unexpected consequence: existing RCU readers, that is, hsr_port_get_hsr() callers, may still be able to read the port list. Instead of checking the return value of each hsr_port_get_hsr(), we can just move it to ->ndo_uninit() which is called after device unregister and synchronize_net(), and we still have RTNL lock there. Fixes: b9a1e627405d ("hsr: implement dellink to clean up resources") Fixes: edf070a0fb45 ("hsr: fix a NULL pointer deref in hsr_dev_xmit()") Reported-by: syzbot+097ef84cdc95843fbaa8@syzkaller.appspotmail.com Cc: Arvid Brodin <arvid.brodin@alten.se> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/hsr/hsr_device.c18
-rw-r--r--net/hsr/hsr_device.h1
-rw-r--r--net/hsr/hsr_netlink.c7
3 files changed, 8 insertions, 18 deletions
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index f0f9b493c47b..f509b495451a 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -227,13 +227,8 @@ static int hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
struct hsr_port *master;
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
- if (master) {
- skb->dev = master->dev;
- hsr_forward_skb(skb, master);
- } else {
- atomic_long_inc(&dev->tx_dropped);
- dev_kfree_skb_any(skb);
- }
+ skb->dev = master->dev;
+ hsr_forward_skb(skb, master);
return NETDEV_TX_OK;
}
@@ -348,7 +343,11 @@ static void hsr_announce(struct timer_list *t)
rcu_read_unlock();
}
-void hsr_dev_destroy(struct net_device *hsr_dev)
+/* This has to be called after all the readers are gone.
+ * Otherwise we would have to check the return value of
+ * hsr_port_get_hsr().
+ */
+static void hsr_dev_destroy(struct net_device *hsr_dev)
{
struct hsr_priv *hsr;
struct hsr_port *port;
@@ -364,8 +363,6 @@ void hsr_dev_destroy(struct net_device *hsr_dev)
del_timer_sync(&hsr->prune_timer);
del_timer_sync(&hsr->announce_timer);
- synchronize_rcu();
-
hsr_del_self_node(&hsr->self_node_db);
hsr_del_nodes(&hsr->node_db);
}
@@ -376,6 +373,7 @@ static const struct net_device_ops hsr_device_ops = {
.ndo_stop = hsr_dev_close,
.ndo_start_xmit = hsr_dev_xmit,
.ndo_fix_features = hsr_fix_features,
+ .ndo_uninit = hsr_dev_destroy,
};
static struct device_type hsr_type = {
diff --git a/net/hsr/hsr_device.h b/net/hsr/hsr_device.h
index d0fa6b0696d2..6d7759c4f5f9 100644
--- a/net/hsr/hsr_device.h
+++ b/net/hsr/hsr_device.h
@@ -14,7 +14,6 @@
void hsr_dev_setup(struct net_device *dev);
int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
unsigned char multicast_spec, u8 protocol_version);
-void hsr_dev_destroy(struct net_device *hsr_dev);
void hsr_check_carrier_and_operstate(struct hsr_priv *hsr);
bool is_hsr_master(struct net_device *dev);
int hsr_get_max_mtu(struct hsr_priv *hsr);
diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index 160edd24de4e..8f8337f893ba 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -69,12 +69,6 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
return hsr_dev_finalize(dev, link, multicast_spec, hsr_version);
}
-static void hsr_dellink(struct net_device *hsr_dev, struct list_head *head)
-{
- hsr_dev_destroy(hsr_dev);
- unregister_netdevice_queue(hsr_dev, head);
-}
-
static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct hsr_priv *hsr;
@@ -119,7 +113,6 @@ static struct rtnl_link_ops hsr_link_ops __read_mostly = {
.priv_size = sizeof(struct hsr_priv),
.setup = hsr_dev_setup,
.newlink = hsr_newlink,
- .dellink = hsr_dellink,
.fill_info = hsr_fill_info,
};