FAT-fs (loop0): bogus number of reserved sectors
FAT-fs (loop0): Can't find a valid FAT filesystem
serio: Serial port pts0
FAT-fs (loop0): bogus number of reserved sectors
FAT-fs (loop0): Can't find a valid FAT filesystem
INFO: task syz-executor7:9602 blocked for more than 140 seconds.
      Not tainted 4.9.123-g8dd3fc2 #27
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D29000  9602   3870 0x00000004
 ffff8801c2078000 ffff8801bff45500 ffff8801bff45500 ffff8801c207c800
 ffff8801db221c18 ffff88019dbe7680 ffffffff839f0dbd ffffffff81237907
 0000000000000000 ffff8801c20788c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839f23bf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839fc7e4>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81eed978>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839fb712>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839fb712>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff815994e1>] inode_lock_shared include/linux/fs.h:776 [inline]
 [<ffffffff815994e1>] lookup_slow+0x141/0x470 fs/namei.c:1645
 [<ffffffff815a5b66>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a84c6>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a84c6>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815adf77>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815ae333>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815ae333>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff81585316>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff81585316>] vfs_fstatat+0xc6/0x170 fs/stat.c:106
 [<ffffffff815865b9>] vfs_lstat fs/stat.c:129 [inline]
 [<ffffffff815865b9>] SYSC_newlstat+0x89/0x100 fs/stat.c:283
 [<ffffffff815868fd>] SyS_newlstat+0x1d/0x30 fs/stat.c:277
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a01c93>] 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: [<ffffffff81368a9c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81368a9c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81428308>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3771:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffe62>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821253c2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor7/9552:
 #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff815e516f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff815e516f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff81598926>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff81598926>] lock_rename+0x236/0x290 fs/namei.c:2857
1 lock held by syz-executor7/9602:
 #0:  (&sb->s_type->i_mutex_key#24){++++++}, at: [<ffffffff815994e1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#24){++++++}, at: [<ffffffff815994e1>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.123-g8dd3fc2 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d868fd08 ffffffff81eb9689 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9fa0 ffff8801d868fd40
 ffffffff81ec49c7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb9689>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb9689>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec49c7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec495a>] 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
 [<ffffffff81369034>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81369034>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81369034>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81369034>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01e5c>] 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: 1924 Comm: jbd2/sda1-8 Not tainted 4.9.123-g8dd3fc2 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cdba9800 task.stack: ffff8801cd418000
RIP: 0010:[<ffffffff839f06ba>] 
c [<ffffffff839f06ba>] delayacct_clear_flag include/linux/delayacct.h:62 [inline]
RIP: 0010:[<ffffffff839f06ba>] 
c [<ffffffff839f06ba>] delayacct_blkio_end include/linux/delayacct.h:94 [inline]
RIP: 0010:[<ffffffff839f06ba>] 
c [<ffffffff839f06ba>] io_schedule_timeout+0x2da/0x390 kernel/sched/core.c:5179
RSP: 0018:ffff8801cd41f718  EFLAGS: 00000246
RAX: 7fffffffffffffff RBX: ffff8801ce2a0da8 RCX: 1ffff10039c541bc
RDX: 0000000000000000 RSI: ffffffff81373e70 RDI: ffff8801ce2a0de0
RBP: ffff8801cd41f738 R08: ffff8801cdbaa0e8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801db221c00
R13: ffff8801cdba9800 R14: 0000000000000002 R15: ffff8801cd41f7f8
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a48b10 CR3: 00000001b6e5c000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 7fffffffffffffff
c ffff8801cd41f7e0
c 0000000000000002
c ffffed0039a83efd
c
 ffff8801cd41f758
c ffffffff839f3809
c ffff8801cd41f7e0
c ffffed0039a83efc
c
 ffff8801cd41f7b0
c ffffffff839f2f53
c ffff8801cd41f880
c ffff8801cd41f7e8
c
Call Trace:
 [<ffffffff839f3809>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff839f3809>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff839f2f53>] __wait_on_bit+0x93/0x120 kernel/sched/wait.c:383
 [<ffffffff839f3288>] out_of_line_wait_on_bit+0xe8/0x120 kernel/sched/wait.c:396
 [<ffffffff81627a6c>] wait_on_bit_io include/linux/wait.h:1070 [inline]
 [<ffffffff81627a6c>] __wait_on_buffer+0x5c/0x70 fs/buffer.c:124
 [<ffffffff81896209>] wait_on_buffer include/linux/buffer_head.h:347 [inline]
 [<ffffffff81896209>] jbd2_journal_commit_transaction+0x3009/0x6050 fs/jbd2/commit.c:804
 [<ffffffff818a93ca>] kjournald2+0x22a/0x830 fs/jbd2/journal.c:224
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01e5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c9b 
c40 
c12 
c00 
c00 
c48 
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c00 
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c48 
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c11 
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c03 
c7e 
c35 
c83 
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c38 
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c<48> 
c83 
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c5b 
c41 
c5c 
c41 
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c48 
c89 
c45 
ce0 
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cb4 
cfd 
c48 
c