INFO: task syz-executor1:15842 blocked for more than 140 seconds.
      Not tainted 4.9.125+ #37
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D25384 15842   2112 0x00000004
 ffff8801a1518000 ffff8801c7486e00 ffff8801d3bce880 ffff8801a01517c0
 ffff8801db621018 ffff8801d2997160 ffffffff8277d092 ffff8801d2997100
 ffffffff8278b918 ffff8801db621000 00ff8801d2997158 ffff8801db6218f0
Call Trace:
 [<ffffffff8277e5bf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff82788be5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1768
 [<ffffffff8277c85a>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5176
 [<ffffffff815b2094>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff815b2094>] dio_await_one fs/direct-io.c:461 [inline]
 [<ffffffff815b2094>] dio_await_completion fs/direct-io.c:515 [inline]
 [<ffffffff815b2094>] do_blockdev_direct_IO fs/direct-io.c:1331 [inline]
 [<ffffffff815b2094>] __blockdev_direct_IO+0x8b54/0xbd10 fs/direct-io.c:1360
 [<ffffffff816b41d8>] ext4_direct_IO_write fs/ext4/inode.c:3507 [inline]
 [<ffffffff816b41d8>] ext4_direct_IO+0x978/0x29c0 fs/ext4/inode.c:3663
 [<ffffffff813fa494>] generic_file_direct_write+0x284/0x510 mm/filemap.c:2655
 [<ffffffff813fa93f>] __generic_file_write_iter+0x21f/0x540 mm/filemap.c:2835
 [<ffffffff8168914d>] ext4_file_write_iter+0x63d/0xd70 fs/ext4/file.c:165
 [<ffffffff815d4a42>] aio_write+0x2f2/0x510 fs/aio.c:1505
 [<ffffffff815d9605>] io_submit_one fs/aio.c:1586 [inline]
 [<ffffffff815d9605>] do_io_submit+0xd35/0x1080 fs/aio.c:1654
 [<ffffffff815d9977>] SYSC_io_submit fs/aio.c:1679 [inline]
 [<ffffffff815d9977>] SyS_io_submit+0x27/0x30 fs/aio.c:1676
 [<ffffffff8100554f>] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282
 [<ffffffff8278c193>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309abc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309abc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813e68fc>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2021:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278a262>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81cdd442>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor3/7551:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff814ee170>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff814ee170>] do_sendfile+0xa80/0xc30 fs/read_write.c:1392
2 locks held by syz-executor1/15842:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815d4b43>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815d4b43>] aio_write+0x3f3/0x510 fs/aio.c:1504
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100
2 locks held by syz-executor1/15850:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81553a3f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81553a3f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff814e37d8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff814e37d8>] do_truncate2+0x128/0x1f0 fs/open.c:61
2 locks held by syz-executor1/15875:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff814eb25b>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff814eb25b>] vfs_write+0x3eb/0x520 fs/read_write.c:556
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100
2 locks held by syz-executor1/15877:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815d4b43>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815d4b43>] aio_write+0x3f3/0x510 fs/aio.c:1504
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81688c32>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.125+ #37
 ffff8801d9907d08 ffffffff81af0ae9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810967d0 ffff8801d9907d40
 ffffffff81afb849 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81af0ae9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af0ae9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81afb849>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81afb7dc>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810968d4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8130a04d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8130a04d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8130a04d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8130a04d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8113d9ad>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278c35c>] 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 skipped: idling at pc 0xffffffff8278ada6