FAT-fs (loop0): error, fat_get_cluster: invalid cluster chain (i_pos 16)
FAT-fs (loop0): error, fat_get_cluster: invalid cluster chain (i_pos 16)
FAT-fs (loop0): error, fat_get_cluster: invalid cluster chain (i_pos 16)
FAT-fs (loop0): error, fat_get_cluster: invalid cluster chain (i_pos 16)
FAT-fs (loop0): error, fat_get_cluster: invalid cluster chain (i_pos 16)
INFO: task syz-executor2:15613 blocked for more than 140 seconds.
      Not tainted 4.9.116-g0137ea2 #18
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D27160 15613   3885 0x00000004
 ffff88019bdbc800 0000000000000000 ffff8801d3974540 ffffffff84629800
 ffff8801db221c18 ffff88019aa57650 ffffffff839ead0d dffffc0000000000
 ffff8801d9c58c10 ffff88019aa57610 00ff88019bdbd0c0 ffff8801db2224e8
Call Trace:
 [<ffffffff839ec30f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff815c7ec2>] d_wait_lookup fs/dcache.c:2455 [inline]
 [<ffffffff815c7ec2>] d_alloc_parallel+0xeb2/0x17c0 fs/dcache.c:2537
 [<ffffffff81594e7c>] lookup_slow+0x19c/0x470 fs/namei.c:1650
 [<ffffffff815a14a6>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3e06>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a3e06>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a98b7>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9c73>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9c73>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff81580c56>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff81580c56>] vfs_fstatat+0xc6/0x170 fs/stat.c:106
 [<ffffffff81581e06>] vfs_stat fs/stat.c:123 [inline]
 [<ffffffff81581e06>] SYSC_newstat+0x86/0xf0 fs/stat.c:270
 [<ffffffff8158220d>] SyS_newstat+0x1d/0x30 fs/stat.c:266
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fbc13>] 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: [<ffffffff8136677c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136677c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425e07>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3759:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f9db2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82120212>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor2/15613:
 #0:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff81594e21>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff81594e21>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.116-g0137ea2 #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8597d08 ffffffff81eb46a9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d8597d40
 ffffffff81ebf9a7 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb46a9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb46a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebf9a7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebf93a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366d14>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d14>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d14>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d14>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ad>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fbddc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 15612 Comm: syz-executor2 Not tainted 4.9.116-g0137ea2 #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019bdbe000 task.stack: ffff8801d3668000
RIP: 0010:[<ffffffff81236342>] 
c [<ffffffff81236342>] atomic_inc arch/x86/include/asm/atomic.h:91 [inline]
RIP: 0010:[<ffffffff81236342>] 
c [<ffffffff81236342>] __lock_acquire+0x192/0x4070 kernel/locking/lockdep.c:3237
RSP: 0018:ffff8801db307ad0  EFLAGS: 00000002
RAX: ffffffff855891b0 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffffffff0b793ed RSI: 0000000000000000 RDI: ffffffff85bc9f68
RBP: ffff8801db307c80 R08: 0000000000000001 R09: 0000000000000001
R10: ffff88019bdbe000 R11: 0000000000000001 R12: 0000000000000001
R13: 0000000000000000 R14: ffffffff85bc9f60 R15: 0000000000000000
FS:  00007feba7d25700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc7aa144000 CR3: 00000001cf5b7000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000001704
c 00000063c2229487
c ffffffff855891b0
c 0000000041b58ab3
c
 0000000000002e47
c ffff88019bdbe958
c ffff88019bdbe8b8
c ffff88019bdbe960
c
 ffff88019bdbe8c0
c ffff88019bdbe8c8
c 1ffff1003b660f66
c ffffffff855581f8
c
Call Trace:
 [<ffffffff8123ac90>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff839fbb2e>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline]
 [<ffffffff839fbb2e>] _raw_spin_lock_irqsave+0x4e/0x62 kernel/locking/spinlock.c:159
 [<ffffffff81f1d067>] debug_object_deactivate+0xf7/0x340 lib/debugobjects.c:475
 [<ffffffff812a4622>] debug_hrtimer_deactivate kernel/time/hrtimer.c:403 [inline]
 [<ffffffff812a4622>] debug_deactivate kernel/time/hrtimer.c:450 [inline]
 [<ffffffff812a4622>] __run_hrtimer kernel/time/hrtimer.c:1224 [inline]
 [<ffffffff812a4622>] __hrtimer_run_queues+0x222/0xe50 kernel/time/hrtimer.c:1319
 [<ffffffff812a5cb1>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1353
 [<ffffffff810b2384>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:935
 [<ffffffff83a013dc>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:959
 [<ffffffff839fd570>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
d [<ffffffff839fb30f>] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 <EOI> 
d [<ffffffff839fb30f>] ? __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:162 [inline]
 <EOI> 
d [<ffffffff839fb30f>] ? _raw_spin_unlock_irqrestore+0x5f/0x70 kernel/locking/spinlock.c:191
 [<ffffffff81221729>] spin_unlock_irqrestore include/linux/spinlock.h:362 [inline]
 [<ffffffff81221729>] prepare_to_wait_event+0x1d9/0x450 kernel/sched/wait.c:238
 [<ffffffff81907a9e>] request_wait_answer+0x22e/0x6e0 fs/fuse/dev.c:459
 [<ffffffff819085a9>] __fuse_request_send+0x109/0x1b0 fs/fuse/dev.c:480
 [<ffffffff819086ad>] fuse_request_send+0x5d/0x70 fs/fuse/dev.c:493
 [<ffffffff81912904>] fuse_simple_request+0x2f4/0x660 fs/fuse/dev.c:551
 [<ffffffff8191aca3>] fuse_lookup_name+0x253/0x5d0 fs/fuse/dir.c:369
 [<ffffffff8191b10d>] fuse_lookup+0xed/0x3a0 fs/fuse/dir.c:406
 [<ffffffff81594f1e>] lookup_slow+0x23e/0x470 fs/namei.c:1668
 [<ffffffff815a14a6>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3e06>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a3e06>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a98b7>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9c73>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9c73>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff81580c56>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff81580c56>] vfs_fstatat+0xc6/0x170 fs/stat.c:106
 [<ffffffff81581e06>] vfs_stat fs/stat.c:123 [inline]
 [<ffffffff81581e06>] SYSC_newstat+0x86/0xf0 fs/stat.c:270
 [<ffffffff8158220d>] SyS_newstat+0x1d/0x30 fs/stat.c:266
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fbc13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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