============================================ WARNING: possible recursive locking detected syzkaller #0 Tainted: G L -------------------------------------------- kworker/u8:22/20829 is trying to acquire lock: ffff888077f0f958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline] ffff888077f0f958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] ffff888077f0f958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x3b5/0xc70 net/sched/sch_generic.c:370 but task is already holding lock: ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline] ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x3b5/0xc70 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 11 locks held by kworker/u8:22/20829: #0: ffff888048152940 ((wq_completion)bond0#21){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc90007617d08 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #2: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: bond_alb_monitor+0xec/0x16f0 drivers/net/bonding/bond_alb.c:1546 #3: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #3: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x296/0x4940 net/core/dev.c:4793 #4: ffff88807af00228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline] #4: ffff88807af00228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #4: ffff88807af00228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline] #4: ffff88807af00228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x24e2/0x4940 net/core/dev.c:4833 #5: ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline] #5: ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] #5: ffff88807b292958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x3b5/0xc70 net/sched/sch_generic.c:370 #6: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #6: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: ip_output+0xb3/0xc10 net/ipv4/ip_output.c:432 #7: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #7: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #7: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x356/0x2400 net/ipv4/ip_output.c:229 #8: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #8: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #8: ffffffff8e9e60c0 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x26/0x2e0 net/ipv4/arp.c:663 #9: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #9: ffffffff8e9e6060 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x296/0x4940 net/core/dev.c:4793 #10: ffff88803309d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline] #10: ffff88803309d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #10: ffff88803309d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline] #10: ffff88803309d228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x24e2/0x4940 net/core/dev.c:4833 stack backtrace: CPU: 0 UID: 0 PID: 20829 Comm: kworker/u8:22 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 Workqueue: bond0 bond_alb_monitor Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x1256/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __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+0x3b5/0xc70 net/sched/sch_generic.c:370 __dev_xmit_skb net/core/dev.c:4211 [inline] __dev_queue_xmit+0x278a/0x4940 net/core/dev.c:4833 dev_queue_xmit include/linux/netdevice.h:3446 [inline] arp_xmit_finish net/ipv4/arp.c:655 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] arp_xmit+0x106/0x2e0 net/ipv4/arp.c:665 arp_send_dst net/ipv4/arp.c:320 [inline] arp_send_dst+0x200/0x280 net/ipv4/arp.c:301 arp_solicit+0x672/0x1070 net/ipv4/arp.c:392 neigh_probe+0xce/0x110 net/core/neighbour.c:1093 __neigh_event_send+0xabe/0x13d0 net/core/neighbour.c:1273 neigh_event_send_probe include/net/neighbour.h:480 [inline] neigh_event_send include/net/neighbour.h:486 [inline] neigh_event_send include/net/neighbour.h:484 [inline] neigh_resolve_output+0x550/0x8f0 net/core/neighbour.c:1600 neigh_output include/net/neighbour.h:560 [inline] ip_finish_output2+0x851/0x2400 net/ipv4/ip_output.c:236 __ip_finish_output.part.0+0x444/0x6f0 net/ipv4/ip_output.c:314 __ip_finish_output net/ipv4/ip_output.c:302 [inline] ip_finish_output net/ipv4/ip_output.c:324 [inline] NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x39b/0xc10 net/ipv4/ip_output.c:437 dst_output include/net/dst.h:470 [inline] ip_local_out+0x193/0x1f0 net/ipv4/ip_output.c:131 iptunnel_xmit+0x722/0xd20 net/ipv4/ip_tunnel_core.c:97 ip_tunnel_xmit+0x1b91/0x3210 net/ipv4/ip_tunnel.c:848 __gre_xmit+0x820/0xb20 net/ipv4/ip_gre.c:491 erspan_xmit+0x55a/0x1ec0 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+0x121/0x760 net/core/dev.c:3905 sch_direct_xmit+0x1b2/0xc70 net/sched/sch_generic.c:372 __dev_xmit_skb net/core/dev.c:4211 [inline] __dev_queue_xmit+0x278a/0x4940 net/core/dev.c:4833 dev_queue_xmit include/linux/netdevice.h:3446 [inline] alb_send_lp_vid+0x31e/0x540 drivers/net/bonding/bond_alb.c:949 alb_send_learning_packets+0xe0/0x2f0 drivers/net/bonding/bond_alb.c:1012 bond_alb_monitor+0x997/0x16f0 drivers/net/bonding/bond_alb.c:1563 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog