============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u8:7/1006 is trying to acquire lock: ffff888060f58998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] ffff888060f58998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] ffff888060f58998 (&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: ffff8880385a0998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] ffff8880385a0998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] ffff8880385a0998 (&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 16 locks held by kworker/u8:7/1006: #0: ffff88803b900938 ((wq_completion)bond1#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88803b900938 ((wq_completion)bond1#2){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc900052dfc40 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc900052dfc40 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #2: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #2: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: bond_alb_monitor+0xf3/0x1810 drivers/net/bonding/bond_alb.c:1546 #3: ffffffff8e059220 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #4: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #5: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #5: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x291/0x3890 net/core/dev.c:4793 #6: ffff888035f00328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #6: ffff888035f00328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline] #6: ffff888035f00328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x113c/0x3890 net/core/dev.c:4833 #7: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #7: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #7: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:127 [inline] #7: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10c/0x2b0 kernel/locking/spinlock_rt.c:135 #8: ffff8880385a0998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #8: ffff8880385a0998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4809 [inline] #8: ffff8880385a0998 (&qdisc_xmit_lock_key#4){+...}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 #9: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #9: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #9: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #9: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 #10: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #10: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #10: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432 #11: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #11: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #11: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x1100 net/ipv4/ip_output.c:229 #12: ffffffff8e059220 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163 #13: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #13: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] #13: ffffffff8e1c3060 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x291/0x3890 net/core/dev.c:4793 #14: ffff888038002328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #14: ffff888038002328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline] #14: ffff888038002328 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x113c/0x3890 net/core/dev.c:4833 #15: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #15: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #15: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:127 [inline] #15: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10c/0x2b0 kernel/locking/spinlock_rt.c:135 stack backtrace: CPU: 0 UID: 0 PID: 1006 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: bond1 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+0x24df/0x2ce0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:45 [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+0x1acf/0x3890 net/core/dev.c:4833 neigh_output include/net/neighbour.h:560 [inline] ip_finish_output2+0xc98/0x1100 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+0x61b/0xd70 net/ipv4/ip_tunnel_core.c:97 ip_tunnel_xmit+0x195e/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+0x2df/0x870 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+0x1acf/0x3890 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 bond_alb_monitor+0x3d0/0x1810 drivers/net/bonding/bond_alb.c:1563 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245