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authorIdo Schimmel <idosch@mellanox.com>2016-10-19 16:57:08 +0300
committerDavid S. Miller <davem@davemloft.net>2016-10-19 10:38:08 -0400
commite4961b0768852d9eb7383e1a5df178eacb714656 (patch)
treeb749c31fe4ef865047c57a693c4374661281cdbf /net
parent3805a938a6c24284863732fd45cec5a04609a224 (diff)
downloadlinux-e4961b0768852d9eb7383e1a5df178eacb714656.tar.bz2
net: core: Correctly iterate over lower adjacency list
Tamir reported the following trace when processing ARP requests received via a vlan device on top of a VLAN-aware bridge: NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [swapper/1:0] [...] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.8.0-rc7 #1 Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016 task: ffff88017edfea40 task.stack: ffff88017ee10000 RIP: 0010:[<ffffffff815dcc73>] [<ffffffff815dcc73>] netdev_all_lower_get_next_rcu+0x33/0x60 [...] Call Trace: <IRQ> [<ffffffffa015de0a>] mlxsw_sp_port_lower_dev_hold+0x5a/0xa0 [mlxsw_spectrum] [<ffffffffa016f1b0>] mlxsw_sp_router_netevent_event+0x80/0x150 [mlxsw_spectrum] [<ffffffff810ad07a>] notifier_call_chain+0x4a/0x70 [<ffffffff810ad13a>] atomic_notifier_call_chain+0x1a/0x20 [<ffffffff815ee77b>] call_netevent_notifiers+0x1b/0x20 [<ffffffff815f2eb6>] neigh_update+0x306/0x740 [<ffffffff815f38ce>] neigh_event_ns+0x4e/0xb0 [<ffffffff8165ea3f>] arp_process+0x66f/0x700 [<ffffffff8170214c>] ? common_interrupt+0x8c/0x8c [<ffffffff8165ec29>] arp_rcv+0x139/0x1d0 [<ffffffff816e505a>] ? vlan_do_receive+0xda/0x320 [<ffffffff815e3794>] __netif_receive_skb_core+0x524/0xab0 [<ffffffff815e6830>] ? dev_queue_xmit+0x10/0x20 [<ffffffffa06d612d>] ? br_forward_finish+0x3d/0xc0 [bridge] [<ffffffffa06e5796>] ? br_handle_vlan+0xf6/0x1b0 [bridge] [<ffffffff815e3d38>] __netif_receive_skb+0x18/0x60 [<ffffffff815e3dc0>] netif_receive_skb_internal+0x40/0xb0 [<ffffffff815e3e4c>] netif_receive_skb+0x1c/0x70 [<ffffffffa06d7856>] br_pass_frame_up+0xc6/0x160 [bridge] [<ffffffffa06d63d7>] ? deliver_clone+0x37/0x50 [bridge] [<ffffffffa06d656c>] ? br_flood+0xcc/0x160 [bridge] [<ffffffffa06d7b14>] br_handle_frame_finish+0x224/0x4f0 [bridge] [<ffffffffa06d7f94>] br_handle_frame+0x174/0x300 [bridge] [<ffffffff815e3599>] __netif_receive_skb_core+0x329/0xab0 [<ffffffff81374815>] ? find_next_bit+0x15/0x20 [<ffffffff8135e802>] ? cpumask_next_and+0x32/0x50 [<ffffffff810c9968>] ? load_balance+0x178/0x9b0 [<ffffffff815e3d38>] __netif_receive_skb+0x18/0x60 [<ffffffff815e3dc0>] netif_receive_skb_internal+0x40/0xb0 [<ffffffff815e3e4c>] netif_receive_skb+0x1c/0x70 [<ffffffffa01544a1>] mlxsw_sp_rx_listener_func+0x61/0xb0 [mlxsw_spectrum] [<ffffffffa005c9f7>] mlxsw_core_skb_receive+0x187/0x200 [mlxsw_core] [<ffffffffa007332a>] mlxsw_pci_cq_tasklet+0x63a/0x9b0 [mlxsw_pci] [<ffffffff81091986>] tasklet_action+0xf6/0x110 [<ffffffff81704556>] __do_softirq+0xf6/0x280 [<ffffffff8109213f>] irq_exit+0xdf/0xf0 [<ffffffff817042b4>] do_IRQ+0x54/0xd0 [<ffffffff8170214c>] common_interrupt+0x8c/0x8c The problem is that netdev_all_lower_get_next_rcu() never advances the iterator, thereby causing the loop over the lower adjacency list to run forever. Fix this by advancing the iterator and avoid the infinite loop. Fixes: 7ce856aaaf13 ("mlxsw: spectrum: Add couple of lower device helper functions") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reported-by: Tamir Winetroub <tamirw@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Acked-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index f1fe26f66458..b09ac57f4348 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5511,10 +5511,14 @@ struct net_device *netdev_all_lower_get_next_rcu(struct net_device *dev,
{
struct netdev_adjacent *lower;
- lower = list_first_or_null_rcu(&dev->all_adj_list.lower,
- struct netdev_adjacent, list);
+ lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
+
+ if (&lower->list == &dev->all_adj_list.lower)
+ return NULL;
+
+ *iter = &lower->list;
- return lower ? lower->dev : NULL;
+ return lower->dev;
}
EXPORT_SYMBOL(netdev_all_lower_get_next_rcu);