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ipvlan: fix multicast processing

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In an IPvlan setup when master is set in loopback mode e.g.

  ethtool -K eth0 set loopback on

  where eth0 is master device for IPvlan setup.

The failure is caused by the faulty logic that determines if the
packet is from TX-path vs. RX-path by just looking at the mac-
addresses on the packet while processing multicast packets.

In the loopback-mode where this crash was happening, the packets
that are sent out are reflected by the NIC and are processed on
the RX path, but mac-address check tricks into thinking this
packet is from TX path and falsely uses dev_forward_skb() to pass
packets to the slave (virtual) devices.

This patch records the path while queueing packets and eliminates
logic of looking at mac-addresses for the same decision.

------------[ cut here ]------------
kernel BUG at include/linux/skbuff.h:1737!
Call Trace:
 [<ffffffff921fbbc2>] dev_forward_skb+0x92/0xd0
 [<ffffffffc031ac65>] ipvlan_process_multicast+0x395/0x4c0 [ipvlan]
 [<ffffffffc031a9a7>] ? ipvlan_process_multicast+0xd7/0x4c0 [ipvlan]
 [<ffffffff91cdfea7>] ? process_one_work+0x147/0x660
 [<ffffffff91cdff09>] process_one_work+0x1a9/0x660
 [<ffffffff91cdfea7>] ? process_one_work+0x147/0x660
 [<ffffffff91ce086d>] worker_thread+0x11d/0x360
 [<ffffffff91ce0750>] ? rescuer_thread+0x350/0x350
 [<ffffffff91ce960b>] kthread+0xdb/0xe0
 [<ffffffff91c05c70>] ? _raw_spin_unlock_irq+0x30/0x50
 [<ffffffff91ce9530>] ? flush_kthread_worker+0xc0/0xc0
 [<ffffffff92348b7a>] ret_from_fork+0x9a/0xd0
 [<ffffffff91ce9530>] ? flush_kthread_worker+0xc0/0xc0

Fixes: ba35f8588f ("ipvlan: Defer multicast / broadcast processing to a work-queue")
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mahesh Bandewar 2016-12-21 17:30:16 -08:00 committed by David S. Miller
parent b1227d019f
commit e252536068
2 changed files with 20 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/net/ipvlan/ipvlan.h
View File

@ -99,6 +99,11 @@ struct ipvl_port {
int count;
};
struct ipvl_skb_cb {
bool tx_pkt;
};
#define IPVL_SKB_CB(_skb) ((struct ipvl_skb_cb *)&((_skb)->cb[0]))
static inline struct ipvl_port *ipvlan_port_get_rcu(const struct net_device *d)
{
return rcu_dereference(d->rx_handler_data);

26
drivers/net/ipvlan/ipvlan_core.c
View File

@ -198,7 +198,7 @@ void ipvlan_process_multicast(struct work_struct *work)
unsigned int mac_hash;
int ret;
u8 pkt_type;
bool hlocal, dlocal;
bool tx_pkt;
__skb_queue_head_init(&list);
@ -211,7 +211,7 @@ void ipvlan_process_multicast(struct work_struct *work)
bool consumed = false;
ethh = eth_hdr(skb);
hlocal = ether_addr_equal(ethh->h_source, port->dev->dev_addr);
tx_pkt = IPVL_SKB_CB(skb)->tx_pkt;
mac_hash = ipvlan_mac_hash(ethh->h_dest);
if (ether_addr_equal(ethh->h_dest, port->dev->broadcast))
@ -219,13 +219,10 @@ void ipvlan_process_multicast(struct work_struct *work)
else
pkt_type = PACKET_MULTICAST;
dlocal = false;
rcu_read_lock();
list_for_each_entry_rcu(ipvlan, &port->ipvlans, pnode) {
if (hlocal && (ipvlan->dev == dev)) {
dlocal = true;
if (tx_pkt && (ipvlan->dev == skb->dev))
continue;
}
if (!test_bit(mac_hash, ipvlan->mac_filters))
continue;
if (!(ipvlan->dev->flags & IFF_UP))
@ -238,7 +235,7 @@ void ipvlan_process_multicast(struct work_struct *work)
consumed = true;
nskb->pkt_type = pkt_type;
nskb->dev = ipvlan->dev;
if (hlocal)
if (tx_pkt)
ret = dev_forward_skb(ipvlan->dev, nskb);
else
ret = netif_rx(nskb);
@ -248,7 +245,7 @@ void ipvlan_process_multicast(struct work_struct *work)
}
rcu_read_unlock();
if (dlocal) {
if (tx_pkt) {
/* If the packet originated here, send it out. */
skb->dev = port->dev;
skb->pkt_type = pkt_type;
@ -480,13 +477,20 @@ out:
}
static void ipvlan_multicast_enqueue(struct ipvl_port *port,
struct sk_buff *skb)
struct sk_buff *skb, bool tx_pkt)
{
if (skb->protocol == htons(ETH_P_PAUSE)) {
kfree_skb(skb);
return;
}
/* Record that the deferred packet is from TX or RX path. By
* looking at mac-addresses on packet will lead to erronus decisions.
* (This would be true for a loopback-mode on master device or a
* hair-pin mode of the switch.)
*/
IPVL_SKB_CB(skb)->tx_pkt = tx_pkt;
spin_lock(&port->backlog.lock);
if (skb_queue_len(&port->backlog) < IPVLAN_QBACKLOG_LIMIT) {
if (skb->dev)
@ -549,7 +553,7 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
} else if (is_multicast_ether_addr(eth->h_dest)) {
ipvlan_skb_crossing_ns(skb, NULL);
ipvlan_multicast_enqueue(ipvlan->port, skb);
ipvlan_multicast_enqueue(ipvlan->port, skb, true);
return NET_XMIT_SUCCESS;
}
@ -646,7 +650,7 @@ static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
*/
if (nskb) {
ipvlan_skb_crossing_ns(nskb, NULL);
ipvlan_multicast_enqueue(port, nskb);
ipvlan_multicast_enqueue(port, nskb, false);
}
}
} else {