From 0bab999063b9bb3f6c9addc52f54c7688f2a51b6 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 8 Jan 2019 12:32:42 -0500 Subject: [PATCH] bonding: update nest level on unlink [ Upstream commit 001e465f09a18857443489a57e74314a3368c805 ] A network device stack with multiple layers of bonding devices can trigger a false positive lockdep warning. Adding lockdep nest levels fixes this. Update the level on both enslave and unlink, to avoid the following series of events .. ip netns add test ip netns exec test bash ip link set dev lo addr 00:11:22:33:44:55 ip link set dev lo down ip link add dev bond1 type bond ip link add dev bond2 type bond ip link set dev lo master bond1 ip link set dev bond1 master bond2 ip link set dev bond1 nomaster ip link set dev bond2 master bond1 .. from still generating a splat: [ 193.652127] ====================================================== [ 193.658231] WARNING: possible circular locking dependency detected [ 193.664350] 4.20.0 #8 Not tainted [ 193.668310] ------------------------------------------------------ [ 193.674417] ip/15577 is trying to acquire lock: [ 193.678897] 00000000a40e3b69 (&(&bond->stats_lock)->rlock#3/3){+.+.}, at: bond_get_stats+0x58/0x290 [ 193.687851] but task is already holding lock: [ 193.693625] 00000000807b9d9f (&(&bond->stats_lock)->rlock#2/2){+.+.}, at: bond_get_stats+0x58/0x290 [..] [ 193.851092] lock_acquire+0xa7/0x190 [ 193.855138] _raw_spin_lock_nested+0x2d/0x40 [ 193.859878] bond_get_stats+0x58/0x290 [ 193.864093] dev_get_stats+0x5a/0xc0 [ 193.868140] bond_get_stats+0x105/0x290 [ 193.872444] dev_get_stats+0x5a/0xc0 [ 193.876493] rtnl_fill_stats+0x40/0x130 [ 193.880797] rtnl_fill_ifinfo+0x6c5/0xdc0 [ 193.885271] rtmsg_ifinfo_build_skb+0x86/0xe0 [ 193.890091] rtnetlink_event+0x5b/0xa0 [ 193.894320] raw_notifier_call_chain+0x43/0x60 [ 193.899225] netdev_change_features+0x50/0xa0 [ 193.904044] bond_compute_features.isra.46+0x1ab/0x270 [ 193.909640] bond_enslave+0x141d/0x15b0 [ 193.913946] do_set_master+0x89/0xa0 [ 193.918016] do_setlink+0x37c/0xda0 [ 193.921980] __rtnl_newlink+0x499/0x890 [ 193.926281] rtnl_newlink+0x48/0x70 [ 193.930238] rtnetlink_rcv_msg+0x171/0x4b0 [ 193.934801] netlink_rcv_skb+0xd1/0x110 [ 193.939103] rtnetlink_rcv+0x15/0x20 [ 193.943151] netlink_unicast+0x3b5/0x520 [ 193.947544] netlink_sendmsg+0x2fd/0x3f0 [ 193.951942] sock_sendmsg+0x38/0x50 [ 193.955899] ___sys_sendmsg+0x2ba/0x2d0 [ 193.960205] __x64_sys_sendmsg+0xad/0x100 [ 193.964687] do_syscall_64+0x5a/0x460 [ 193.968823] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 7e2556e40026 ("bonding: avoid lockdep confusion in bond_get_stats()") Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/bonding/bond_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index cf64a36..65c5a65 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1928,6 +1928,9 @@ static int __bond_release_one(struct net_device *bond_dev, if (!bond_has_slaves(bond)) { bond_set_carrier(bond); eth_hw_addr_random(bond_dev); + bond->nest_level = SINGLE_DEPTH_NESTING; + } else { + bond->nest_level = dev_get_nest_level(bond_dev) + 1; } unblock_netpoll_tx(); -- 2.7.4