============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u8:31/22465 is trying to acquire lock: ffff88805af80558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline] ffff88805af80558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4713 [inline] ffff88805af80558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:345 but task is already holding lock: ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline] ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4713 [inline] ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:345 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 11 locks held by kworker/u8:31/22465: #0: ffff88807e7ce148 ((wq_completion)bond10#3){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88807e7ce148 ((wq_completion)bond10#3){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90010fb7c40 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90010fb7c40 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #2: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #2: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: bond_alb_monitor+0xf8/0x17e0 drivers/net/bonding/bond_alb.c:1546 #3: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline] #3: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x274/0x38a0 net/core/dev.c:4761 #4: ffff8880789a5228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:353 [inline] #4: ffff8880789a5228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:202 [inline] #4: ffff8880789a5228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4173 [inline] #4: ffff8880789a5228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x1002/0x38a0 net/core/dev.c:4802 #5: ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline] #5: ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4713 [inline] #5: ffff88807e1fd958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:345 #6: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #6: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #6: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450 net/ipv4/ip_output.c:433 #7: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #7: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #7: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3c2/0x1070 net/ipv4/ip_output.c:230 #8: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #8: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #8: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:664 #9: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline] #9: ffffffff8e760340 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x274/0x38a0 net/core/dev.c:4761 #10: ffff88804aa3e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:353 [inline] #10: ffff88804aa3e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:202 [inline] #10: ffff88804aa3e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4173 [inline] #10: ffff88804aa3e228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x1002/0x38a0 net/core/dev.c:4802 stack backtrace: CPU: 0 UID: 0 PID: 22465 Comm: kworker/u8:31 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: bond10 bond_alb_monitor Call Trace: 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+0x253f/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 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:154 spin_lock include/linux/spinlock.h:341 [inline] __netif_tx_lock include/linux/netdevice.h:4713 [inline] sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:4186 [inline] __dev_queue_xmit+0x1538/0x38a0 net/core/dev.c:4802 NF_HOOK+0x33a/0x3c0 include/linux/netfilter.h:-1 arp_xmit+0x16c/0x270 net/ipv4/arp.c:666 arp_solicit+0xbe0/0xe40 net/ipv4/arp.c:393 neigh_probe net/core/neighbour.c:1096 [inline] __neigh_event_send+0xf05/0x1530 net/core/neighbour.c:1276 neigh_event_send_probe include/net/neighbour.h:480 [inline] neigh_event_send include/net/neighbour.h:486 [inline] neigh_resolve_output+0x198/0x750 net/core/neighbour.c:1603 neigh_output include/net/neighbour.h:556 [inline] ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 iptunnel_xmit+0x59f/0xa00 net/ipv4/ip_tunnel_core.c:84 ip_tunnel_xmit+0x193a/0x1f20 net/ipv4/ip_tunnel.c:845 __gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:490 erspan_xmit+0xa81/0x1670 net/ipv4/ip_gre.c:749 __netdev_start_xmit include/linux/netdevice.h:5275 [inline] netdev_start_xmit include/linux/netdevice.h:5284 [inline] xmit_one net/core/dev.c:3871 [inline] dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3887 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:347 __dev_xmit_skb net/core/dev.c:4186 [inline] __dev_queue_xmit+0x1538/0x38a0 net/core/dev.c:4802 dev_queue_xmit include/linux/netdevice.h:3384 [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 bond_alb_monitor+0x3d5/0x17e0 drivers/net/bonding/bond_alb.c:1563 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245