============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u4:12/8172 is trying to acquire lock: ffff88802eb01218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88802eb01218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3899 [inline] ffff88802eb01218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x1f6f/0x36b0 net/core/dev.c:4404 but task is already holding lock: ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3856 [inline] ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x126a/0x36b0 net/core/dev.c:4404 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); *** DEADLOCK *** May be due to missing lock nesting notation 9 locks held by kworker/u4:12/8172: #0: ffff88805d8bbd38 ((wq_completion)bond5#5){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff88805d8bbd38 ((wq_completion)bond5#5){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc90004bbfd00 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90004bbfd00 ((work_completion)(&(&bond->alb_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #2: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #2: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #2: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: bond_alb_monitor+0xf9/0x17e0 drivers/net/bonding/bond_alb.c:1547 #3: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:838 [inline] #3: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26b/0x36b0 net/core/dev.c:4363 #4: ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #4: ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3856 [inline] #4: ffff888056a3e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x126a/0x36b0 net/core/dev.c:4404 #5: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #5: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #5: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: ip_output+0x60/0x3b0 net/ipv4/ip_output.c:431 #6: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #6: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #6: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x457/0x11e0 net/ipv4/ip_output.c:228 #7: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #7: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #7: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:662 #8: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:838 [inline] #8: ffffffff8d132040 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26b/0x36b0 net/core/dev.c:4363 stack backtrace: CPU: 1 PID: 8172 Comm: kworker/u4:12 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: bond5 bond_alb_monitor Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5dbc/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 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] __dev_xmit_skb net/core/dev.c:3899 [inline] __dev_queue_xmit+0x1f6f/0x36b0 net/core/dev.c:4404 NF_HOOK+0x331/0x3b0 include/linux/netfilter.h:-1 arp_xmit+0x16c/0x270 net/ipv4/arp.c:664 arp_solicit+0xc02/0xe40 net/ipv4/arp.c:392 neigh_probe net/core/neighbour.c:1080 [inline] __neigh_event_send+0xed1/0x1440 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+0xd3a/0x11e0 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436 iptunnel_xmit+0x4f0/0x920 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1cbc/0x2410 net/ipv4/ip_tunnel.c:844 __gre_xmit net/ipv4/ip_gre.c:478 [inline] gre_tap_xmit+0x4fe/0x6f0 net/ipv4/ip_gre.c:757 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3632 [inline] dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3648 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3869 [inline] __dev_queue_xmit+0x179c/0x36b0 net/core/dev.c:4404 dev_queue_xmit include/linux/netdevice.h:3113 [inline] alb_send_lp_vid+0x2fc/0x4e0 drivers/net/bonding/bond_alb.c:949 alb_send_learning_packets+0x12d/0x300 drivers/net/bonding/bond_alb.c:1012 bond_alb_monitor+0x3d6/0x17e0 drivers/net/bonding/bond_alb.c:1564 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa5d/0x15d0 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