Total swap = 0kB
1965969 pages RAM
0 pages HighMem/MovableOnly
321064 pages reserved
INFO: task syz-executor5:13507 blocked for more than 140 seconds.
      Not tainted 4.9.113-g9905591 #14
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29544 13507   3809 0x00000004
 ffff8801970be000 ffff8801c56d64c0 ffff8801c56d64c0 ffff8801d6174800
 ffff8801db221c18 ffff8801d41c7ce8 ffffffff839e929d ffff8801970be8c8
 ffffed0032e17d18 ffff8801970be000 00fffc0000000000 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea89f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839eb223>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff839ef6a6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839ef6a6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff815d81ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
 [<ffffffff8157687e>] fdget_pos include/linux/file.h:66 [inline]
 [<ffffffff8157687e>] SYSC_write fs/read_write.c:599 [inline]
 [<ffffffff8157687e>] SyS_write+0x7e/0x1c0 fs/read_write.c:596
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fa193>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/520:
 #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 getty/3700:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8342>] 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-executor5/13507:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d81ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by syz-executor5/13581:
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0a8f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0a8f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff8156a838>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff8156a838>] do_truncate2+0x128/0x1f0 fs/open.c:61

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

NMI backtrace for cpu 0
CPU: 0 PID: 520 Comm: khungtaskd Not tainted 4.9.113-g9905591 #14
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d84c7d08 ffffffff81eb32a9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d84c7d40
 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
 [<ffffffff839fa35c>] 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: 6 Comm: kworker/u4:0 Not tainted 4.9.113-g9905591 #14
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn
c (flush-7:5)
c
task: ffff8801d9a38000 task.stack: ffff8801d9a40000
RIP: 0010:[<ffffffff8135ea96>] 
c [<ffffffff8135ea96>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff8135ea96>] 
c [<ffffffff8135ea96>] check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:[<ffffffff8135ea96>] 
c [<ffffffff8135ea96>] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801d9a47510  EFLAGS: 00000246
RAX: ffff8801d9a38000 RBX: ffffea0006e73f00 RCX: 1ffffffff0886881
RDX: 0000000000000000 RSI: ffffffff81438d00 RDI: ffffffff84434408
RBP: ffff8801d9a47510 R08: ffff8801d9a38960 R09: 0000000000000001
R10: ffff8801d9a38000 R11: 1ffff1003b347127 R12: ffff8801939429a8
R13: dffffc0000000000 R14: ffffea0006e73f1c R15: ffffea0006e73f00
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42cf39000 CR3: 00000001d4c71000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d9a47578
c ffffffff81438d00
c ffffffff81438be0
c ffffea0006e73f20
c
 ffffea0006e73f00
c 0000000000000008
c ffff8801d5d9b190
c ffffea0006e73f00
c
 0000000000000003
c 0000000000000007
c dffffc0000000000
c 0000000002420848
c
Call Trace:
 [<ffffffff81438d00>] rcu_read_unlock include/linux/rcupdate.h:930 [inline]
 [<ffffffff81438d00>] find_get_entry+0x120/0x540 mm/filemap.c:1132
 [<ffffffff8143a05b>] pagecache_get_page+0x4b/0x720 mm/filemap.c:1203
 [<ffffffff81625459>] find_or_create_page include/linux/pagemap.h:309 [inline]
 [<ffffffff81625459>] grow_dev_page fs/buffer.c:1005 [inline]
 [<ffffffff81625459>] grow_buffers fs/buffer.c:1078 [inline]
 [<ffffffff81625459>] __getblk_slow fs/buffer.c:1105 [inline]
 [<ffffffff81625459>] __getblk_gfp+0x249/0x710 fs/buffer.c:1386
 [<ffffffff81628d3d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818cc63b>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818cc63b>] __fat_write_inode+0x2ab/0x980 fs/fat/inode.c:844
 [<ffffffff818d0849>] fat_write_inode+0x79/0x170 fs/fat/inode.c:893
 [<ffffffff8160238d>] write_inode fs/fs-writeback.c:1180 [inline]
 [<ffffffff8160238d>] __writeback_single_inode+0x86d/0x1020 fs/fs-writeback.c:1379
 [<ffffffff8160368c>] writeback_sb_inodes+0x4ac/0xe70 fs/fs-writeback.c:1584
 [<ffffffff8160414b>] __writeback_inodes_wb+0xfb/0x1e0 fs/fs-writeback.c:1653
 [<ffffffff816048d2>] wb_writeback+0x512/0xbd0 fs/fs-writeback.c:1762
 [<ffffffff8160e200>] wb_check_old_data_flush fs/fs-writeback.c:1877 [inline]
 [<ffffffff8160e200>] wb_do_writeback fs/fs-writeback.c:1901 [inline]
 [<ffffffff8160e200>] wb_workfn+0x850/0xdb0 fs/fs-writeback.c:1930
 [<ffffffff8118d181>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118df76>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119d0ad>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fa35c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
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c11 
c