4.20-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn willemb@google.com
[ 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 syzkaller@googlegroups.com Signed-off-by: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_main.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1948,6 +1948,9 @@ static int __bond_release_one(struct net 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();