============================================ WARNING: possible recursive locking detected 6.1.140-syzkaller #0 Not tainted -------------------------------------------- syz.1.344/6016 is trying to acquire lock: ffff0000c3508218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000c3508218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3925 [inline] ffff0000c3508218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1a24/0x309c net/core/dev.c:4300 but task is already holding lock: ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0xe58/0x309c net/core/dev.c:4300 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 11 locks held by syz.1.344/6016: #0: ffff0000c084e460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x23c/0x7c4 fs/read_write.c:580 #1: ffff0000dafdc1b0 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0000dafdc1b0 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: generic_file_write_iter+0x84/0x2b0 mm/filemap.c:4003 #2: ffff800008017c40 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline] #2: ffff800008017c40 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd0/0x964 kernel/time/timer.c:1494 #3: ffff800015246d40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #4: ffff800015246d40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #5: ffff800015246da0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #6: ffff800015246d40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #7: ffff800015246da0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #8: ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #8: ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #8: ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] #8: ffff0000f1c65258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0xe58/0x309c net/core/dev.c:4300 #9: ffff800015246d40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #10: ffff800015246da0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 stack backtrace: CPU: 1 PID: 6016 Comm: syz.1.344 Not tainted 6.1.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 __lock_acquire+0x18b4/0x6544 kernel/locking/lockdep.c:-1 lock_acquire+0x20c/0x644 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x54/0x6c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:3925 [inline] __dev_queue_xmit+0x1a24/0x309c net/core/dev.c:4300 dev_queue_xmit include/linux/netdevice.h:3051 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xb9c/0x10a4 net/ipv4/ip_output.c:228 __ip_finish_output+0x1b0/0x448 net/ipv4/ip_output.c:-1 ip_finish_output+0x40/0x268 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0x314/0x414 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:453 [inline] ip_local_out+0x120/0x15c net/ipv4/ip_output.c:126 iptunnel_xmit+0x3f8/0x8cc net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x149c/0x2044 net/ipv4/ip_tunnel.c:858 __gre_xmit net/ipv4/ip_gre.c:474 [inline] gre_tap_xmit+0x408/0x5f4 net/ipv4/ip_gre.c:751 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x244/0x8e0 net/core/dev.c:3674 sch_direct_xmit+0x204/0x480 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3895 [inline] __dev_queue_xmit+0x1384/0x309c net/core/dev.c:4300 dev_queue_xmit include/linux/netdevice.h:3051 [inline] bond_dev_queue_xmit+0x98/0x138 drivers/net/bonding/bond_main.c:307 bond_do_alb_xmit+0x5dc/0x7cc drivers/net/bonding/bond_alb.c:1358 bond_tlb_xmit+0x38/0x48 drivers/net/bonding/bond_alb.c:1416 __bond_start_xmit drivers/net/bonding/bond_main.c:5503 [inline] bond_start_xmit+0x988/0x1888 drivers/net/bonding/bond_main.c:5525 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x244/0x8e0 net/core/dev.c:3674 __dev_queue_xmit+0x155c/0x309c net/core/dev.c:4334 dev_queue_xmit include/linux/netdevice.h:3051 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0xd2c/0x1844 net/ipv6/ip6_output.c:138 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x594/0x930 net/ipv6/ip6_output.c:216 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x500 net/ipv6/ip6_output.c:237 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xc38/0x1680 net/ipv6/ndisc.c:513 ndisc_send_rs+0x378/0x514 net/ipv6/ndisc.c:723 addrconf_rs_timer+0x2f4/0x574 net/ipv6/addrconf.c:3985 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x460/0x6bc kernel/time/timer.c:1820 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1833 handle_softirqs+0x318/0xc6c kernel/softirq.c:578 __do_softirq+0x14/0x20 kernel/softirq.c:612 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:893 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85 invoke_softirq kernel/softirq.c:459 [inline] __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:661 irq_exit_rcu+0x14/0x84 kernel/softirq.c:673 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline] el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] _raw_spin_unlock_irq+0x44/0x90 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:401 [inline] shmem_get_folio_gfp+0x1610/0x2040 mm/shmem.c:1982 shmem_get_folio mm/shmem.c:2072 [inline] shmem_write_begin+0xf4/0x46c mm/shmem.c:2556 generic_perform_write+0x230/0x4b0 mm/filemap.c:3846 __generic_file_write_iter+0x168/0x37c mm/filemap.c:3974 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:4006 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x5ac/0x7c4 fs/read_write.c:584 ksys_write+0x120/0x210 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585