INFO: task syz-executor2:24406 blocked for more than 120 seconds.
      Not tainted 4.9.92-g4fb542f #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D27976 24406   3763 0x20020004
 ffff8801bf576000 0000000000000000 ffff8801ce45aa00 ffffffff84429880
 ffff8801db221b98 ffff8801cbf67a90 ffffffff838c49cd 1ffff100397ecf46
 ffffffff85316f38 0000000041b58ab3 00ffffff841a4570 ffff8801db222468
Call Trace:
 [<ffffffff838c5fcf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3556
 [<ffffffff838d23e1>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff838c41aa>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5178
 [<ffffffff838c7903>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff838c7903>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff838c7903>] wait_for_common_io kernel/sched/completion.c:107 [inline]
 [<ffffffff838c7903>] wait_for_completion_io+0x203/0x2e0 kernel/sched/completion.c:155
 [<ffffffff81ce3c7b>] submit_bio_wait+0x11b/0x180 block/bio.c:885
 [<ffffffff81d164cb>] blkdev_issue_flush+0x15b/0x220 block/blk-flush.c:518
 [<ffffffff8162c8c5>] blkdev_fsync+0x85/0xb0 fs/block_dev.c:378
 [<ffffffff81617ecc>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff81618092>] vfs_fsync fs/sync.c:209 [inline]
 [<ffffffff81618092>] do_fsync+0x42/0xb0 fs/sync.c:219
 [<ffffffff81618839>] SYSC_fdatasync fs/sync.c:233 [inline]
 [<ffffffff81618839>] SyS_fdatasync+0x19/0x20 fs/sync.c:231
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff838d6fd0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/515:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813643ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813643ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423dc0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3559:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d582c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3656:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838d3a72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff820080d2>] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133

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

NMI backtrace for cpu 1
CPU: 1 PID: 515 Comm: khungtaskd Not tainted 4.9.92-g4fb542f #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8617d08 ffffffff81d9c509 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b7d90 ffff8801d8617d40
 ffffffff81da7847 0000000000000001 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81d9c509>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d9c509>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da7847>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81da77da>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e94>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364984>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364984>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364984>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364984>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ab0d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838d5a9c>] 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 4.9.92-g4fb542f #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84429880 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff81238cab>] 
c [<ffffffff81238cab>] __lock_release kernel/locking/lockdep.c:3546 [inline]
RIP: 0010:[<ffffffff81238cab>] 
c [<ffffffff81238cab>] lock_release+0x2ab/0xb80 kernel/locking/lockdep.c:3775
RSP: 0018:ffff8801db207c68  EFLAGS: 00000046
RAX: 0000000000000007 RBX: ffffffff8596b260 RCX: ffffffff84429880
RDX: 0000000000000000 RSI: ffffffff8596b260 RDI: ffffffff8442a18c
RBP: ffff8801db207d10 R08: ffffffff8442a188 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffffffff088542c R12: dffffc0000000000
R13: ffffffff8442a168 R14: ffffffff8442a140 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb131e3000 CR3: 00000001cbe42000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000046
c ffffffff84429880
c 0000000000000000
c 0000000000000000
c
 0000000000000000
c ffff8801db207d08
c 0000000000000046
c 0000000000000000
c
 ffffffff81e04e87
c ffffffff8442a138
c ffffffff8442a140
c 0000000000000046
c
Call Trace:
 [<ffffffff838d4f8f>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
 [<ffffffff838d4f8f>] _raw_spin_unlock_irqrestore+0x1f/0x70 kernel/locking/spinlock.c:191
 [<ffffffff81e04fa4>] debug_object_deactivate+0x214/0x340 lib/debugobjects.c:503
 [<ffffffff8129c8d6>] debug_timer_deactivate kernel/time/timer.c:727 [inline]
 [<ffffffff8129c8d6>] debug_deactivate kernel/time/timer.c:779 [inline]
 [<ffffffff8129c8d6>] detach_timer kernel/time/timer.c:824 [inline]
 [<ffffffff8129c8d6>] expire_timers kernel/time/timer.c:1348 [inline]
 [<ffffffff8129c8d6>] __run_timers kernel/time/timer.c:1658 [inline]
 [<ffffffff8129c8d6>] run_timer_softirq+0x446/0x1590 kernel/time/timer.c:1684
 [<ffffffff838dc4bb>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff81148dc7>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff81148dc7>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff838db0a1>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff838db0a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff838d7230>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
d [<ffffffff838d44d6>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:53
 [<ffffffff838d3b15>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff838d3b15>] default_idle+0x55/0x360 arch/x86/kernel/process.c:295
 [<ffffffff81069fa0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:286
 [<ffffffff838d4935>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff81220725>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff81220725>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff81220725>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff838c179c>] rest_init+0x183/0x189 init/main.c:408
 [<ffffffff84a73943>] start_kernel+0x67e/0x6b2 init/main.c:663
 [<ffffffff84a7229a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84a723db>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:177
Code: 
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c