syzbot

netlink: 'syz.5.6231': attribute type 1 has an invalid length.
bond6: entered promiscuous mode
bond6: entered allmulticast mode
8021q: adding VLAN 0 to HW filter on device bond6
erspan1: entered allmulticast mode
bond6: (slave erspan1): making interface the new active one
erspan1: entered promiscuous mode
============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G             L     
--------------------------------------------
syz.5.6231/29391 is trying to acquire lock:
ffff8880586b9558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff8880586b9558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline]
ffff8880586b9558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370

but task is already holding lock:
ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline]
ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&qdisc_xmit_lock_key#4);
  lock(&qdisc_xmit_lock_key#4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

9 locks held by syz.5.6231/29391:
 #0: ffffffff9034b0c8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff9034b0c8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff9034b0c8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8fdeaec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8fdeaec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8fdeaec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
 #2: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
 #2: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline]
 #2: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x37f0 net/core/dev.c:4793
 #3: ffff88803016e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
 #3: ffff88803016e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
 #3: ffff88803016e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline]
 #3: ffff88803016e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x112b/0x37f0 net/core/dev.c:4833
 #4: ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #4: ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline]
 #4: ffff8880349ee558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
 #5: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #5: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #5: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432
 #6: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #6: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #6: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x10b0 net/ipv4/ip_output.c:229
 #7: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
 #7: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline]
 #7: ffffffff8e959c80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x37f0 net/core/dev.c:4793
 #8: ffff88807b67d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
 #8: ffff88807b67d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
 #8: ffff88807b67d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline]
 #8: ffff88807b67d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x112b/0x37f0 net/core/dev.c:4833

stack backtrace:
CPU: 0 UID: 0 PID: 29391 Comm: syz.5.6231 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x24df/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
 spin_lock include/linux/spinlock.h:342 [inline]
 __netif_tx_lock include/linux/netdevice.h:4809 [inline]
 sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
 __dev_xmit_skb net/core/dev.c:4211 [inline]
 __dev_queue_xmit+0x1754/0x37f0 net/core/dev.c:4833
 neigh_output include/net/neighbour.h:560 [inline]
 ip_finish_output2+0xc4b/0x10b0 net/ipv4/ip_output.c:236
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x29f/0x450 net/ipv4/ip_output.c:437
 iptunnel_xmit+0x626/0xd10 net/ipv4/ip_tunnel_core.c:97
 ip_tunnel_xmit+0x195b/0x2040 net/ipv4/ip_tunnel.c:848
 __gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491
 erspan_xmit+0xad5/0x1590 net/ipv4/ip_gre.c:750
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905
 sch_direct_xmit+0x257/0x4c0 net/sched/sch_generic.c:372
 __dev_xmit_skb net/core/dev.c:4211 [inline]
 __dev_queue_xmit+0x1754/0x37f0 net/core/dev.c:4833
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 alb_send_lp_vid+0x348/0x550 drivers/net/bonding/bond_alb.c:949
 alb_send_learning_packets+0x12c/0x300 drivers/net/bonding/bond_alb.c:1012
 alb_fasten_mac_swap+0x45d/0xf70 drivers/net/bonding/bond_alb.c:1076
 bond_alb_handle_active_change+0xc85/0xf50 drivers/net/bonding/bond_alb.c:1774
 bond_change_active_slave+0x1098/0x36d0 drivers/net/bonding/bond_main.c:1309
 bond_select_active_slave+0x8a6/0xcd0 drivers/net/bonding/bond_main.c:1379
 bond_enslave+0x239c/0x3b10 drivers/net/bonding/bond_main.c:2298
 do_set_master+0x563/0x720 net/core/rtnetlink.c:3020
 rtnl_newlink_create+0x641/0xb00 net/core/rtnetlink.c:3927
 __rtnl_newlink net/core/rtnetlink.c:4044 [inline]
 rtnl_newlink+0x167f/0x1bd0 net/core/rtnetlink.c:4159
 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2684
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3d679ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb3d769f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb3d6a15fa0 RCX: 00007fb3d679ce59
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000000000000007
RBP: 00007fb3d6832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3d6a16038 R14: 00007fb3d6a15fa0 R15: 00007fb3d6b3fa48
 </TASK>
bond6: (slave erspan1): Enslaving as an active interface with an up link
syz.5.6231 (29391) used greatest stack depth: 17832 bytes left