============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u4:77/5556 is trying to acquire lock: ffff8880789b90d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880789b90d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4342 [inline] ffff8880789b90d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: sch_direct_xmit+0x162/0x4a0 net/sched/sch_generic.c:343 but task is already holding lock: ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4342 [inline] ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: sch_direct_xmit+0x162/0x4a0 net/sched/sch_generic.c:343 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qdisc_xmit_lock_key#2); lock(&qdisc_xmit_lock_key#2); *** DEADLOCK *** May be due to missing lock nesting notation 10 locks held by kworker/u4:77/5556: #0: ffff888076af2138 ((wq_completion)bond3#4){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc9000580fd00 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: bond_alb_monitor+0xf0/0x1810 drivers/net/bonding/bond_alb.c:1547 #3: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #3: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x281/0x3810 net/core/dev.c:4294 #4: ffff88805919e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff88805919e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:196 [inline] #4: ffff88805919e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3919 [inline] #4: ffff88805919e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x131c/0x3810 net/core/dev.c:4337 #5: ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #5: ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4342 [inline] #5: ffff8880578b08d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: sch_direct_xmit+0x162/0x4a0 net/sched/sch_generic.c:343 #6: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #6: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #6: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: ip_output+0x57/0x400 net/ipv4/ip_output.c:426 #7: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #7: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #7: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x407/0x1220 net/ipv4/ip_output.c:221 #8: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #8: ffffffff8cb2dbc0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x281/0x3810 net/core/dev.c:4294 #9: ffff888054b05258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #9: ffff888054b05258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:196 [inline] #9: ffff888054b05258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3919 [inline] #9: ffff888054b05258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x131c/0x3810 net/core/dev.c:4337 stack backtrace: CPU: 0 PID: 5556 Comm: kworker/u4:77 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bond3 bond_alb_monitor Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 __lock_acquire+0x12c8/0x7c40 kernel/locking/lockdep.c:-1 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4342 [inline] sch_direct_xmit+0x162/0x4a0 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:3932 [inline] __dev_queue_xmit+0x180d/0x3810 net/core/dev.c:4337 neigh_output include/net/neighbour.h:549 [inline] ip_finish_output2+0xd53/0x1220 net/ipv4/ip_output.c:228 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0x2d9/0x400 net/ipv4/ip_output.c:434 iptunnel_xmit+0x4a1/0x880 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1d6a/0x25d0 net/ipv4/ip_tunnel.c:844 __gre_xmit net/ipv4/ip_gre.c:474 [inline] erspan_xmit+0x994/0x1550 net/ipv4/ip_gre.c:723 __netdev_start_xmit include/linux/netdevice.h:4891 [inline] netdev_start_xmit include/linux/netdevice.h:4905 [inline] xmit_one net/core/dev.c:3695 [inline] dev_hard_start_xmit+0x292/0x8b0 net/core/dev.c:3711 sch_direct_xmit+0x24d/0x4a0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3932 [inline] __dev_queue_xmit+0x180d/0x3810 net/core/dev.c:4337 alb_send_learning_packets+0x129/0x300 drivers/net/bonding/bond_alb.c:1012 bond_alb_monitor+0x3cd/0x1810 drivers/net/bonding/bond_alb.c:1564 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295