FAT-fs (loop2): Unrecognized mount option ":" or missing value
FAT-fs (loop2): Unrecognized mount option ":" or missing value
INFO: task kworker/u4:4:4110 blocked for more than 120 seconds.
      Not tainted 4.9.101-gaef17a5 #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:4    D25224  4110      2 0x00000000
Workqueue: events_unbound flush_to_ldisc
 ffff8801d52e1800 0000000000000000 ffff8801ccfab9c0 ffff8801c0248000
 ffff8801db221b98 ffff8801d4b7f8c8 ffffffff839e39bd ffff8801d52e20c8
 ffffed003aa5c418 ffff8801d52e1800 00fffc0000000000 ffff8801db222468
Call Trace:
 [<ffffffff839e4fbf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839e5943>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff839e9dc6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839e9dc6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff8211a500>] commit_echoes+0x120/0x1b0 drivers/tty/n_tty.c:764
 [<ffffffff82123158>] n_tty_receive_char_fast drivers/tty/n_tty.c:1418 [inline]
 [<ffffffff82123158>] n_tty_receive_buf_fast drivers/tty/n_tty.c:1578 [inline]
 [<ffffffff82123158>] __receive_buf drivers/tty/n_tty.c:1613 [inline]
 [<ffffffff82123158>] n_tty_receive_buf_common+0x1878/0x2300 drivers/tty/n_tty.c:1711
 [<ffffffff82123c13>] n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1746
 [<ffffffff8212970f>] tty_ldisc_receive_buf+0xaf/0x190 drivers/tty/tty_buffer.c:455
 [<ffffffff8212a713>] receive_buf drivers/tty/tty_buffer.c:474 [inline]
 [<ffffffff8212a713>] flush_to_ldisc+0x253/0x370 drivers/tty/tty_buffer.c:533
 [<ffffffff8118ae71>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118bc66>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119ad9d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f4a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136477c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136477c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423c90>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3771:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f2a62>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211cd32>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
6 locks held by kworker/u4:4/4110:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118ad7e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118ad7e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118ad7e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118ad7e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&buf->work)){+.+...}, at: [<ffffffff8118adb8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82127ee0>] tty_ldisc_ref+0x20/0x80 drivers/tty/tty_ldisc.c:296
 #3:  (&port->buf.lock/1){+.+...}, at: [<ffffffff8212a546>] flush_to_ldisc+0x86/0x370 drivers/tty/tty_buffer.c:505
 #4:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff8212196b>] n_tty_receive_buf_common+0x8b/0x2300 drivers/tty/n_tty.c:1674
 #5:  (&ldata->output_lock){+.+...}, at: [<ffffffff8211a500>] commit_echoes+0x120/0x1b0 drivers/tty/n_tty.c:764

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.101-gaef17a5 #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d96bfd08 ffffffff81eb1009 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7da0 ffff8801d96bfd40
 ffffffff81ebc307 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb1009>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb1009>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebc307>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebc29a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7ea4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364d14>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364d14>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364d14>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364d14>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad9d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f4a5c>] 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: 18999 Comm: syz-executor5 Not tainted 4.9.101-gaef17a5 #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801b7d08000 task.stack: ffff880193b70000
RIP: 0010:[<ffffffff82118c5e>] 
c [<ffffffff82118c5e>] __process_echoes+0x64e/0x780 drivers/tty/n_tty.c:738
RSP: 0018:ffff880193b77980  EFLAGS: 00000246
RAX: 0000000000040000 RBX: ffffc90009aff000 RCX: ffffc9000c9b6000
RDX: 0000000000040000 RSI: ffffffff82118c5e RDI: ffffc90009b002e5
RBP: ffff880193b779e8 R08: ffff8801b7d08938 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000060fd73084
R13: 0000000000000265 R14: dffffc0000000000 R15: 0000000000000085
FS:  00007f0b23a9d700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000fa6298 CR3: 00000001ba6ed000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff880193b779c0
c 0000000000000000
c ffffc90009b01278
c ffffed003adb4295
c
 ffff8801d6da14ac
c ffffc90009aff020
c 0000000000001f00
c ffff8801d6da1100
c
 ffffc90009b01300
c ffffc90009aff000
c dffffc0000000000
c ffffc90009aff020
c
Call Trace:
 [<ffffffff82122614>] flush_echoes drivers/tty/n_tty.c:801 [inline]
 [<ffffffff82122614>] __receive_buf drivers/tty/n_tty.c:1617 [inline]
 [<ffffffff82122614>] n_tty_receive_buf_common+0xd34/0x2300 drivers/tty/n_tty.c:1711
 [<ffffffff82123c50>] n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1740
 [<ffffffff8211406f>] tiocsti drivers/tty/tty_io.c:2314 [inline]
 [<ffffffff8211406f>] tty_ioctl+0xc8f/0x2270 drivers/tty/tty_io.c:2905
 [<ffffffff815b052c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b052c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b052c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b15af>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b15af>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c48 
c89 
cfa 
c48 
cc1 
ce8 
c03 
c83 
ce2 
c07 
c42 
c0f 
cb6 
c04 
c30 
c38 
cd0 
c7f 
c08 
c84 
cc0 
c0f 
c85 
c99 
c00 
c00 
c00 
c42 
c80 
cbc 
c3b 
c60 
c12 
c00 
c00 
c82 
c74 
c0f 
ce8 
c32 
c3e 
c24 
cff 
c<4d> 
c8d 
c7c 
c24 
c02 
ce9 
c58 
cff 
cff 
cff 
ce8 
c23 
c3e 
c24 
cff 
c4d 
c8d 
c7c 
c24 
c03 
ce9 
c