FAT-fs (loop2): Unrecognized mount option "/dev/ppp" or missing value
INFO: task syz-executor7:10561 blocked for more than 140 seconds.
      Not tainted 4.9.113-g47bbcd6 #10
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D29112 10561   9248 0x00000004
 ffff88019dcb6000 0000000000000000 ffff8801c2a1df80 ffff88019d7e6000
 ffff8801db221c18 ffff88019c99f790 ffffffff839e909d ffffffff81235647
 0000000000000000 ffff88019dcb68c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea69f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839f4ac4>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81ee7558>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839f39f2>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839f39f2>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff81594cb1>] inode_lock_shared include/linux/fs.h:776 [inline]
 [<ffffffff81594cb1>] lookup_slow+0x141/0x470 fs/namei.c:1645
 [<ffffffff815a1336>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3c96>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a3c96>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a9747>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9b03>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9b03>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff8156c82d>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff8156c82d>] SYSC_chroot fs/open.c:505 [inline]
 [<ffffffff8156c82d>] SyS_chroot+0x9d/0x280 fs/open.c:499
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f93>] 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: [<ffffffff8136675c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136675c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425de7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3679:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d81ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff81572cce>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff81572cce>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3777:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8142>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211ee22>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor7/10561:
 #0:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff81594cb1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff81594cb1>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.113-g47bbcd6 #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d860fd08 ffffffff81eb32a9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d860fd40
 ffffffff81ebe5a7 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb32a9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb32a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebe5a7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebe53a>] 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
 [<ffffffff81366cf4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366cf4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366cf4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366cf4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ad>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fa15c>] 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: 10505 Comm: syz-executor7 Not tainted 4.9.113-g47bbcd6 #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019de7b000 task.stack: ffff8801c14a8000
RIP: 0010:[<ffffffff8122fc73>] 
c [<ffffffff8122fc73>] match_held_lock+0x63/0x570 kernel/locking/lockdep.c:3408
RSP: 0018:ffff8801c14af7e0  EFLAGS: 00000006
RAX: 0000000000000003 RBX: ffff88019de7b000 RCX: ffffc90000120000
RDX: 0000000000000000 RSI: ffffffff846def20 RDI: ffff88019de7b93a
RBP: ffff8801c14af810 R08: ffff88019de7b938 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed0033bcf718
R13: ffff88019de7b918 R14: ffffffff846def20 R15: 0000000000000002
FS:  00007f5a55f8e700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f971711a280 CR3: 00000001c63e4000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801bb7cae80
c ffff88019de7b000
c ffffed0033bcf718
c ffff88019de7b8c8
c
 ffffffff846def20
c 0000000000000002
c ffff8801c14af850
c ffffffff81230222
c
 ffff88019de7b8c0
c 0000000000000246
c ffff88019de7b000
c ffffffff846def20
c
Call Trace:
 [<ffffffff81230222>] __lock_is_held+0xa2/0xf0 kernel/locking/lockdep.c:3597
 [<ffffffff81230a54>] lock_is_held+0xb4/0x140 kernel/locking/lockdep.c:3794
 [<ffffffff811bb557>] ___might_sleep+0x1c7/0x260 kernel/sched/core.c:7954
 [<ffffffff811bb685>] __might_sleep+0x95/0x1a0 kernel/sched/core.c:7945
 [<ffffffff81907ab4>] request_wait_answer+0x124/0x6e0 fs/fuse/dev.c:459
 [<ffffffff819086c9>] __fuse_request_send+0x109/0x1b0 fs/fuse/dev.c:480
 [<ffffffff819087cd>] fuse_request_send+0x5d/0x70 fs/fuse/dev.c:493
 [<ffffffff81912a24>] fuse_simple_request+0x2f4/0x660 fs/fuse/dev.c:551
 [<ffffffff8191adc3>] fuse_lookup_name+0x253/0x5d0 fs/fuse/dir.c:369
 [<ffffffff8191b22d>] fuse_lookup+0xed/0x3a0 fs/fuse/dir.c:406
 [<ffffffff81593e4c>] lookup_real fs/namei.c:1522 [inline]
 [<ffffffff81593e4c>] __lookup_hash+0x11c/0x190 fs/namei.c:1542
 [<ffffffff815aa046>] filename_create+0x1a6/0x490 fs/namei.c:3640
 [<ffffffff815ac49b>] user_path_create fs/namei.c:3697 [inline]
 [<ffffffff815ac49b>] SYSC_mkdirat fs/namei.c:3841 [inline]
 [<ffffffff815ac49b>] SyS_mkdirat+0xbb/0x260 fs/namei.c:3833
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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