============================================ WARNING: possible recursive locking detected 6.1.134-syzkaller #0 Not tainted -------------------------------------------- syz.8.3831/15640 is trying to acquire lock: ffff0000dc024218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000dc024218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3925 [inline] ffff0000dc024218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1b38/0x34d4 net/core/dev.c:4300 but task is already holding lock: ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0xf04/0x34d4 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 10 locks held by syz.8.3831/15640: #0: ffff0000d4a73460 (&sb->s_type->i_lock_key){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #0: ffff0000d4a73460 (&sb->s_type->i_lock_key){+.+.}-{2:2}, at: filemap_remove_folio+0xbc/0x1cc mm/filemap.c:253 #1: ffff800008017c60 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline] #1: ffff800008017c60 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd0/0xa1c kernel/time/timer.c:1494 #2: ffff800015cd7820 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #3: ffff800015cd7820 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #4: ffff800015cd7880 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #5: ffff800015cd7820 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #6: ffff800015cd7880 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #7: ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #7: ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #7: ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] #7: ffff0000d780c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0xf04/0x34d4 net/core/dev.c:4300 #8: ffff800015cd7820 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #9: ffff800015cd7880 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 stack backtrace: CPU: 1 PID: 15640 Comm: syz.8.3831 Not tainted 6.1.134-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 lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 validate_chain kernel/locking/lockdep.c:-1 [inline] __lock_acquire+0x6310/0x7680 kernel/locking/lockdep.c:5049 lock_acquire+0x26c/0x7cc 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+0x1b38/0x34d4 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+0xc9c/0x11f0 net/ipv4/ip_output.c:228 __ip_finish_output+0x1b0/0x458 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+0x330/0x49c net/ipv4/ip_output.c:430 dst_output include/net/dst.h:453 [inline] ip_local_out+0x120/0x160 net/ipv4/ip_output.c:126 iptunnel_xmit+0x410/0x8f0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x18bc/0x1f9c net/ipv4/ip_tunnel.c:858 __gre_xmit net/ipv4/ip_gre.c:474 [inline] gre_tap_xmit+0x414/0x600 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+0x25c/0x9a4 net/core/dev.c:3674 sch_direct_xmit+0x234/0x548 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3895 [inline] __dev_queue_xmit+0x1438/0x34d4 net/core/dev.c:4300 __bond_start_xmit include/linux/netdevice.h:-1 [inline] bond_start_xmit+0xec4/0x1990 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+0x25c/0x9a4 net/core/dev.c:3674 __dev_queue_xmit+0x161c/0x34d4 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+0xdc4/0x1bc0 net/ipv6/ip6_output.c:138 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x5a4/0x940 net/ipv6/ip6_output.c:216 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 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+0xcb0/0x18a0 net/ipv6/ndisc.c:513 ndisc_send_rs+0x3b8/0x4e0 net/ipv6/ndisc.c:723 addrconf_rs_timer+0x300/0x58c net/ipv6/addrconf.c:3982 call_timer_fn+0x1c0/0xa1c kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1820 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1833 handle_softirqs+0x318/0xd58 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+0x264/0x4d4 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+0x38/0x68 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] filemap_remove_folio+0xdc/0x1cc mm/filemap.c:256 truncate_inode_folio+0x6c/0x84 mm/truncate.c:195 shmem_undo_range+0x428/0x16b8 mm/shmem.c:942 shmem_truncate_range mm/shmem.c:1062 [inline] shmem_evict_inode+0x200/0x8a8 mm/shmem.c:1171 evict+0x418/0x894 fs/inode.c:705 iput_final fs/inode.c:1834 [inline] iput+0x7c0/0x8a4 fs/inode.c:1860 dentry_unlink_inode+0x37c/0x4bc fs/dcache.c:405 __dentry_kill+0x324/0x5e4 fs/dcache.c:611 dentry_kill+0xc8/0x250 fs/dcache.c:-1 dput+0x218/0x454 fs/dcache.c:918 __fput+0x488/0x7c8 fs/file_table.c:328 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x240/0x2f0 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x550/0x1a84 kernel/exit.c:871 do_group_exit+0x194/0x22c kernel/exit.c:1021 get_signal+0x143c/0x1528 kernel/signal.c:2871 do_signal arch/arm64/kernel/signal.c:1076 [inline] do_notify_resume+0x388/0x2cb8 arch/arm64/kernel/signal.c:1129 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585