===================================== WARNING: bad unlock balance detected! 5.5.0-rc5-syzkaller #0 Not tainted ------------------------------------- kworker/u4:7/417 is trying to release lock (&dev->qdisc_xmit_lock_key) at: [] spin_unlock include/linux/spinlock.h:378 [inline] [] __netif_tx_unlock include/linux/netdevice.h:3966 [inline] [] sch_direct_xmit+0x3fa/0xd30 net/sched/sch_generic.c:315 but there are no more locks to release! other info that might help us debug this: 9 locks held by kworker/u4:7/417: #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc900024e7dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4c5fc8 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xaf0 net/core/net_namespace.c:559 #3: ffffc90000da8d50 ((&ndev->rs_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #3: ffffc90000da8d50 ((&ndev->rs_timer)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 #4: ffffffff899a3f00 (rcu_read_lock){....}, at: ip6_nd_hdr net/ipv6/ndisc.c:463 [inline] #4: ffffffff899a3f00 (rcu_read_lock){....}, at: ndisc_send_skb+0x7fe/0x1490 net/ipv6/ndisc.c:499 #5: ffffffff899a3ec0 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #5: ffffffff899a3ec0 (rcu_read_lock_bh){....}, at: ip6_finish_output2+0x214/0x25c0 net/ipv6/ip6_output.c:102 #6: ffffffff899a3ec0 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35c0 net/core/dev.c:3948 #7: ffff8880a4958250 (&dev->qdisc_tx_busylock_key#21){+...}, at: spin_trylock include/linux/spinlock.h:348 [inline] #7: ffff8880a4958250 (&dev->qdisc_tx_busylock_key#21){+...}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #7: ffff8880a4958250 (&dev->qdisc_tx_busylock_key#21){+...}, at: __dev_xmit_skb net/core/dev.c:3611 [inline] #7: ffff8880a4958250 (&dev->qdisc_tx_busylock_key#21){+...}, at: __dev_queue_xmit+0x2412/0x35c0 net/core/dev.c:3982 #8: ffff8880a4958138 (&dev->qdisc_running_key#21){+...}, at: dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 stack backtrace: CPU: 1 PID: 417 Comm: kworker/u4:7 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_unlock_imbalance_bug kernel/locking/lockdep.c:4008 [inline] print_unlock_imbalance_bug.cold+0x114/0x123 kernel/locking/lockdep.c:3984 __lock_release kernel/locking/lockdep.c:4242 [inline] lock_release+0x5f2/0x960 kernel/locking/lockdep.c:4503 __raw_spin_unlock include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:378 [inline] __netif_tx_unlock include/linux/netdevice.h:3966 [inline] sch_direct_xmit+0x3fa/0xd30 net/sched/sch_generic.c:315 __dev_xmit_skb net/core/dev.c:3621 [inline] __dev_queue_xmit+0x2707/0x35c0 net/core/dev.c:3982 dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0xfbe/0x25c0 net/ipv6/ip6_output.c:116 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:142 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xf1f/0x1490 net/ipv6/ndisc.c:505 ndisc_send_rs+0x134/0x720 net/ipv6/ndisc.c:699 addrconf_rs_timer+0x30f/0x6e0 net/ipv6/addrconf.c:3879 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:lock_is_held_type+0x272/0x320 kernel/locking/lockdep.c:4524 Code: ff df c7 83 94 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 88 00 00 00 48 83 3d ee 01 39 08 00 74 31 48 8b 7d c0 57 9d <0f> 1f 44 00 00 48 83 c4 20 44 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d RSP: 0018:ffffc900024e7a88 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff132669b RBX: ffff8880a8584180 RCX: ffff8880a8584a18 RDX: dffffc0000000000 RSI: ffffffff899a3e80 RDI: 0000000000000282 RBP: ffffc900024e7ad0 R08: ffff8880a8584180 R09: ffff8880a8584a10 R10: fffffbfff14f6948 R11: ffffffff8a7b4a47 R12: 0000000000000000 R13: ffff8880a8584a68 R14: ffffffff899a3e80 R15: 0000000000000003 lock_is_held include/linux/lockdep.h:361 [inline] ___might_sleep+0x205/0x2c0 kernel/sched/core.c:6765 inet_twsk_purge+0x102/0x7c0 net/ipv4/inet_timewait_sock.c:267 dccp_v6_exit_batch+0x1a/0x20 net/dccp/ipv6.c:1114 ops_exit_list.isra.0+0x10c/0x160 net/core/net_namespace.c:175 cleanup_net+0x538/0xaf0 net/core/net_namespace.c:597 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352