============================================ WARNING: possible recursive locking detected 5.15.179-syzkaller #0 Not tainted -------------------------------------------- ksoftirqd/0/14 is trying to acquire lock: ffff0000db308218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000db308218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3908 [inline] ffff0000db308218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1964/0x2ac8 net/core/dev.c:4252 but task is already holding lock: ffff0000d1572258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] ffff0000d1572258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin+0x130/0x2bc include/net/sch_generic.h:173 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** May be due to missing lock nesting notation 9 locks held by ksoftirqd/0/14: #0: ffff80001bd57a00 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #0: ffff80001bd57a00 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd0/0x8f0 kernel/time/timer.c:1441 #1: ffff800014d41b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #2: ffff800014d41bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #3: ffff800014d41bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #4: ffff800014d41b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #5: ffff800014d41bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #6: ffff0000d1572258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #6: ffff0000d1572258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin+0x130/0x2bc include/net/sch_generic.h:173 #7: ffff800014d41bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #8: ffff800014d41bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 validate_chain kernel/locking/lockdep.c:-1 [inline] __lock_acquire+0x62bc/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __dev_xmit_skb net/core/dev.c:3908 [inline] __dev_queue_xmit+0x1964/0x2ac8 net/core/dev.c:4252 dev_queue_xmit+0x24/0x34 net/core/dev.c:4320 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip_finish_output2+0xd3c/0x131c net/ipv4/ip_output.c:228 __ip_finish_output+0x1b0/0x458 net/ipv4/ip_output.c:-1 ip_finish_output+0x40/0x218 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0x330/0x49c net/ipv4/ip_output.c:430 dst_output include/net/dst.h:452 [inline] ip_local_out+0x120/0x160 net/ipv4/ip_output.c:126 iptunnel_xmit+0x410/0x900 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1490/0x20dc net/ipv4/ip_tunnel.c:838 __gre_xmit net/ipv4/ip_gre.c:474 [inline] gre_tap_xmit+0x404/0x5f0 net/ipv4/ip_gre.c:751 __netdev_start_xmit include/linux/netdevice.h:5027 [inline] netdev_start_xmit include/linux/netdevice.h:5041 [inline] xmit_one net/core/dev.c:3648 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3664 sch_direct_xmit+0x2e0/0x484 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3883 [inline] __dev_queue_xmit+0x1488/0x2ac8 net/core/dev.c:4252 dev_queue_xmit+0x24/0x34 net/core/dev.c:4320 bond_dev_queue_xmit+0x94/0x134 drivers/net/bonding/bond_main.c:304 bond_do_alb_xmit+0x558/0x70c drivers/net/bonding/bond_alb.c:1327 bond_tlb_xmit+0x3c/0x4c drivers/net/bonding/bond_alb.c:1382 __bond_start_xmit drivers/net/bonding/bond_main.c:5142 [inline] bond_start_xmit+0xa78/0x1550 drivers/net/bonding/bond_main.c:5164 __netdev_start_xmit include/linux/netdevice.h:5027 [inline] netdev_start_xmit include/linux/netdevice.h:5041 [inline] xmit_one net/core/dev.c:3648 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3664 __dev_queue_xmit+0x1378/0x2ac8 net/core/dev.c:4287 dev_queue_xmit+0x24/0x34 net/core/dev.c:4320 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x132c/0x1cec net/ipv6/ip6_output.c:130 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:201 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:452 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xc94/0x18a8 net/ipv6/ndisc.c:513 ndisc_send_rs+0x49c/0x604 net/ipv6/ndisc.c:707 addrconf_rs_timer+0x308/0x5a8 net/ipv6/addrconf.c:3959 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x384/0xdbc kernel/softirq.c:558 run_ksoftirqd+0x6c/0x29c kernel/softirq.c:925 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870