===================================== WARNING: bad unlock balance detected! 5.5.0-rc5-syzkaller #0 Not tainted ------------------------------------- swapper/0/0 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: 4 locks held by swapper/0/0: #0: ffffc90000007d50 ((&n->timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #0: ffffc90000007d50 ((&n->timer)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 #1: ffffffff899a3ec0 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35c0 net/core/dev.c:3948 #2: ffff888092408250 (&dev->qdisc_tx_busylock_key#25){+...}, at: spin_trylock include/linux/spinlock.h:348 [inline] #2: ffff888092408250 (&dev->qdisc_tx_busylock_key#25){+...}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #2: ffff888092408250 (&dev->qdisc_tx_busylock_key#25){+...}, at: __dev_xmit_skb net/core/dev.c:3611 [inline] #2: ffff888092408250 (&dev->qdisc_tx_busylock_key#25){+...}, at: __dev_queue_xmit+0x2412/0x35c0 net/core/dev.c:3982 #3: ffff888092408138 (&dev->qdisc_running_key#25){+...}, at: dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 arp_xmit_finish net/ipv4/arp.c:630 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] arp_xmit+0xdf/0x3f0 net/ipv4/arp.c:639 arp_send_dst.part.0+0x202/0x290 net/ipv4/arp.c:317 arp_send_dst net/ipv4/arp.c:390 [inline] arp_solicit+0x748/0x1370 net/ipv4/arp.c:389 neigh_probe+0xd0/0x120 net/core/neighbour.c:1009 neigh_timer_handler+0x59d/0x10e0 net/core/neighbour.c:1090 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:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: a8 86 de f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 44 49 54 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 34 49 54 00 fb f4 cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 7e 55 8e f9 e8 49 RSP: 0018:ffffffff89807ce8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff132669e RBX: ffffffff8987a140 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff8987a9d4 RBP: ffffffff89807d18 R08: ffffffff8987a140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff8a7b4a40 R14: 0000000000000000 R15: 0000000000000000 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242