============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u4:27/8326 is trying to acquire lock: ffff88805cf818d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88805cf818d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] ffff88805cf818d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: sch_direct_xmit+0x15a/0x4a0 net/sched/sch_generic.c:343 but task is already holding lock: ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: sch_direct_xmit+0x15a/0x4a0 net/sched/sch_generic.c:343 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qdisc_xmit_lock_key#3); lock(&qdisc_xmit_lock_key#3); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by kworker/u4:27/8326: #0: ffff88802b81a938 ((wq_completion)bond1#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff88802b81a938 ((wq_completion)bond1#2){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc900041efd00 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc900041efd00 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #2: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: bond_alb_monitor+0xf2/0x17f0 drivers/net/bonding/bond_alb.c:1547 #3: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:838 [inline] #3: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x245/0x35a0 net/core/dev.c:4350 #4: ffff88801dfcd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff88801dfcd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #4: ffff88801dfcd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3843 [inline] #4: ffff88801dfcd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x1106/0x35a0 net/core/dev.c:4391 #5: ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #5: ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] #5: ffff8880300924d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: sch_direct_xmit+0x15a/0x4a0 net/sched/sch_generic.c:343 #6: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #6: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #6: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45c/0x11d0 net/ipv4/ip_output.c:228 #7: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #7: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #7: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:661 #8: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:838 [inline] #8: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x245/0x35a0 net/core/dev.c:4350 #9: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #9: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #9: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x186/0x17f0 net/bridge/br_device.c:50 #10: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:838 [inline] #10: ffffffff8cd2ff80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x245/0x35a0 net/core/dev.c:4350 #11: ffff88807a94e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #11: ffff88807a94e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #11: ffff88807a94e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3843 [inline] #11: ffff88807a94e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x1106/0x35a0 net/core/dev.c:4391 stack backtrace: CPU: 0 PID: 8326 Comm: kworker/u4:27 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: bond1 bond_alb_monitor Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4406 [inline] sch_direct_xmit+0x15a/0x4a0 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:3856 [inline] __dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4391 dev_queue_xmit include/linux/netdevice.h:3113 [inline] br_dev_queue_push_xmit+0x6a6/0x850 net/bridge/br_forward.c:53 NF_HOOK+0x340/0x3d0 include/linux/netfilter.h:304 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 NF_HOOK+0x340/0x3d0 include/linux/netfilter.h:304 __br_forward+0x41f/0x600 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xb5/0x150 net/bridge/br_forward.c:191 br_flood+0x31b/0x680 net/bridge/br_forward.c:237 br_dev_xmit+0xa56/0x17f0 net/bridge/br_device.c:90 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3619 [inline] dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3635 __dev_queue_xmit+0x1a64/0x35a0 net/core/dev.c:4425 NF_HOOK+0x307/0x390 include/linux/netfilter.h:-1 arp_xmit+0x16c/0x270 net/ipv4/arp.c:663 arp_solicit+0xbe5/0xe20 net/ipv4/arp.c:392 neigh_probe net/core/neighbour.c:1080 [inline] __neigh_event_send+0xf0a/0x14c0 net/core/neighbour.c:1247 neigh_event_send_probe include/net/neighbour.h:467 [inline] neigh_event_send include/net/neighbour.h:473 [inline] neigh_resolve_output+0x19b/0x730 net/core/neighbour.c:1552 neigh_output include/net/neighbour.h:543 [inline] ip_finish_output2+0xd21/0x11d0 net/ipv4/ip_output.c:235 iptunnel_xmit+0x53e/0x9c0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1c12/0x2360 net/ipv4/ip_tunnel.c:844 erspan_xmit+0x9c0/0x1440 net/ipv4/ip_gre.c:729 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3619 [inline] dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3635 sch_direct_xmit+0x252/0x4a0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3856 [inline] __dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4391 dev_queue_xmit include/linux/netdevice.h:3113 [inline] alb_send_lp_vid+0x2e7/0x4c0 drivers/net/bonding/bond_alb.c:949 alb_send_learning_packets+0x10e/0x2c0 drivers/net/bonding/bond_alb.c:1012 bond_alb_monitor+0x3e5/0x17f0 drivers/net/bonding/bond_alb.c:1564 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293