IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
INFO: task syz-executor6:5026 blocked for more than 140 seconds.
      Not tainted 4.9.124-g09eb2ba #83
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D29624  5026   3758 0x00000004
 ffff880194aa6000 ffff8801d90f9a40 ffff8801d90f9a40 ffff8801cfc39800
 ffff8801db321c18 ffff8801a5637c78 ffffffff839f0afd ffff880194aa68c8
 ffffed0032954d18 ffff880194aa6000 00fffc0000000000 ffff8801db3224e8
Call Trace:
 [<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839f2a83>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839f6f06>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839f6f06>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277
 [<ffffffff82f53f11>] snd_seq_release+0x51/0xe0 sound/core/seq/seq_clientmgr.c:367
 [<ffffffff8157ca73>] __fput+0x263/0x700 fs/file_table.c:208
 [<ffffffff8157cf95>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8119a66c>] task_work_run+0x10c/0x180 kernel/task_work.c:116
 [<ffffffff8100559c>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100559c>] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161
 [<ffffffff810064d4>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff810064d4>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff810064d4>] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287
 [<ffffffff83a019d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3539:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815dc7ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3637:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor6/5026:
 #0:  (register_mutex#3){+.+.+.}, at: [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277
1 lock held by syz-executor5/5048:
 #0:  (register_mutex#3){+.+.+.}, at: [<ffffffff82f53d4f>] seq_free_client+0x1f/0xf0 sound/core/seq/seq_clientmgr.c:277

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8877d08 ffffffff81eb95e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9fa0 ffff8801d8877d40
 ffffffff81ec4927 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec48ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810ba0a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.124-g09eb2ba #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84629800 task.stack: ffffffff84600000
RIP: 0010:[<ffffffff81ecae4e>] 
c [<ffffffff81ecae4e>] rb_set_parent_color include/linux/rbtree_augmented.h:117 [inline]
RIP: 0010:[<ffffffff81ecae4e>] 
c [<ffffffff81ecae4e>] __rb_insert lib/rbtree.c:134 [inline]
RIP: 0010:[<ffffffff81ecae4e>] 
c [<ffffffff81ecae4e>] rb_insert_color+0x5de/0xca0 lib/rbtree.c:420
RSP: 0018:ffff8801db207a78  EFLAGS: 00000046
RAX: ffff8801d96c6090 RBX: ffff8801c6d81890 RCX: ffff8801c6d81890
RDX: 1ffff10038db0313 RSI: ffff8801db221cc8 RDI: ffff8801d4018090
RBP: ffff8801db207ab8 R08: ffff8801d40180d0 R09: ffff8801d96c6090
R10: 000000000000017c R11: 0000000000000000 R12: ffff8801d96c6090
R13: ffff8801c6d81891 R14: ffff8801ce28e090 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdd67b66000 CR3: 00000001cc366000 CR4: 00000000001606f0
Stack:
 ffff8801d4018080
c ffff8801db207b18
c ffffffff811ee1a5
c ffff8801d4018090
c
 ffff8801d96c6098
c dffffc0000000000
c ffff8801d4018080
c ffffed003a80301a
c
 ffff8801db207b18
c ffffffff811e4fd8
c ffff8801d40180a8
c ffff8801db2225a0
c
Call Trace:
 [<ffffffff811e4fd8>] __enqueue_entity+0x138/0x230 kernel/sched/fair.c:581
 [<ffffffff811f215a>] enqueue_entity kernel/sched/fair.c:3659 [inline]
 [<ffffffff811f215a>] enqueue_task_fair+0x24a/0x2680 kernel/sched/fair.c:4823
 [<ffffffff811ccd23>] enqueue_task kernel/sched/core.c:774 [inline]
 [<ffffffff811ccd23>] activate_task+0x153/0x280 kernel/sched/core.c:790
 [<ffffffff811cdde5>] ttwu_activate kernel/sched/core.c:1702 [inline]
 [<ffffffff811cdde5>] ttwu_do_activate+0xd5/0x200 kernel/sched/core.c:1761
 [<ffffffff811d1160>] ttwu_queue kernel/sched/core.c:1917 [inline]
 [<ffffffff811d1160>] try_to_wake_up+0x760/0xec0 kernel/sched/core.c:2130
 [<ffffffff811d18d0>] wake_up_process+0x10/0x20 kernel/sched/core.c:2205
 [<ffffffff8129aad5>] process_timeout+0x15/0x20 kernel/time/timer.c:1724
 [<ffffffff8129ac43>] call_timer_fn+0x163/0x6e0 kernel/time/timer.c:1319
 [<ffffffff812a1da7>] expire_timers kernel/time/timer.c:1359 [inline]
 [<ffffffff812a1da7>] __run_timers kernel/time/timer.c:1658 [inline]
 [<ffffffff812a1da7>] run_timer_softirq+0x1047/0x1590 kernel/time/timer.c:1684
 [<ffffffff83a085c0>] __do_softirq+0x210/0x940 kernel/softirq.c:288
 [<ffffffff8114d554>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff8114d554>] irq_exit+0x114/0x150 kernel/softirq.c:409
 [<ffffffff83a071a1>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff83a071a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:962
 [<ffffffff83a03330>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
d [<ffffffff83a00606>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:55
 [<ffffffff839ffc45>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff839ffc45>] default_idle+0x55/0x360 arch/x86/kernel/process.c:437
 [<ffffffff8106ae20>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428
 [<ffffffff83a00a65>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff81225495>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff81225495>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff81225495>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff839ed8cc>] rest_init+0x183/0x189 init/main.c:409
 [<ffffffff84c98943>] start_kernel+0x67e/0x6b2 init/main.c:664
 [<ffffffff84c9729a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84c973db>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:177
Code: 
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c