INFO: task syz-executor1:16578 blocked for more than 140 seconds.
      Not tainted 4.9.117-g8b21e85 #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D28656 16578  12973 0x00000004
 ffff8801d5ec1800 ffff8801ccce1f80 ffff8801b6a90540 ffff88019cc39800
 ffff8801db221c18 ffff8801d8f7f590 ffffffff839ebd0d ffffffff81235687
 0000000000000000 ffff8801d5ec20c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839ed30f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839f7734>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81ee8e98>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839f6662>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839f6662>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff81595061>] inode_lock_shared include/linux/fs.h:776 [inline]
 [<ffffffff81595061>] lookup_slow+0x141/0x470 fs/namei.c:1645
 [<ffffffff815a16e6>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a4046>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a4046>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a9af7>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9d35>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9d35>] kern_path+0x45/0x70 fs/namei.c:2406
 [<ffffffff81633e22>] lookup_bdev.part.25+0x72/0x180 fs/block_dev.c:1901
 [<ffffffff81633f8e>] lookup_bdev+0x5e/0x80 fs/block_dev.c:1922
 [<ffffffff816cb0aa>] quotactl_block fs/quota/quota.c:808 [inline]
 [<ffffffff816cb0aa>] SYSC_quotactl fs/quota/quota.c:867 [inline]
 [<ffffffff816cb0aa>] SyS_quotactl+0x1ba/0x1240 fs/quota/quota.c:832
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fcc13>] 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: [<ffffffff813667fc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667fc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426017>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3685:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d859c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157307e>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3783:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fadb2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821207f2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor1/16578:
 #0:  (&type->i_mutex_dir_key#5){++++++}, at: [<ffffffff81595061>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&type->i_mutex_dir_key#5){++++++}, at: [<ffffffff81595061>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.117-g8b21e85 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8617d08 ffffffff81eb4be9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d8617d40
 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4be9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4be9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfee7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe7a>] 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
 [<ffffffff81366d94>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d94>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d94>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d94>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fcddc>] 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: 3685 Comm: rs:main Q:Reg Not tainted 4.9.117-g8b21e85 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801b9221800 task.stack: ffff8801b7d40000
RIP: 0010:[<ffffffff8122fc5b>] 
c [<ffffffff8122fc5b>] match_held_lock+0xb/0x570 kernel/locking/lockdep.c:3404
RSP: 0018:ffff8801b7d475f8  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: ffff8801b9221800 RCX: ffff8801db321d68
RDX: 0000000000000000 RSI: ffff8801db321c18 RDI: ffff8801b9222168
RBP: ffff8801b7d47638 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff10037244436 R12: ffffed0037244418
R13: ffff8801b92220c8 R14: ffff8801db321c18 R15: 0000000000000004
FS:  00007ff7bf400700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6ed601edfa CR3: 00000001b9137000 CR4: 00000000001606f0
DR0: 00000000200001c0 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801b7d47638
c ffffffff81230262
c ffff8801b92220c0
c 0000000000000046
c
 ffff8801b9221800
c ffff8801db321c18
c ffff8801db321c00
c 0000000000000001
c
 ffff8801b7d47660
c ffffffff81230a94
c ffff8801cdb9c880
c ffff8801db321ca0
c
Call Trace:
 [<ffffffff81230a94>] lock_is_held+0xb4/0x140 kernel/locking/lockdep.c:3794
 [<ffffffff811ebd70>] rq_clock_task kernel/sched/sched.h:821 [inline]
 [<ffffffff811ebd70>] cfs_rq_clock_task kernel/sched/fair.c:4696 [inline]
 [<ffffffff811ebd70>] update_load_avg+0xb70/0x1ea0 kernel/sched/fair.c:3319
 [<ffffffff811effe7>] enqueue_entity kernel/sched/fair.c:3647 [inline]
 [<ffffffff811effe7>] enqueue_task_fair+0x3b7/0x2680 kernel/sched/fair.c:4823
 [<ffffffff811caa43>] enqueue_task kernel/sched/core.c:774 [inline]
 [<ffffffff811caa43>] activate_task+0x153/0x280 kernel/sched/core.c:790
 [<ffffffff811cbb05>] ttwu_activate kernel/sched/core.c:1702 [inline]
 [<ffffffff811cbb05>] ttwu_do_activate+0xd5/0x200 kernel/sched/core.c:1761
 [<ffffffff811cee80>] ttwu_queue kernel/sched/core.c:1917 [inline]
 [<ffffffff811cee80>] try_to_wake_up+0x760/0xec0 kernel/sched/core.c:2130
 [<ffffffff811cf710>] default_wake_function+0x30/0x50 kernel/sched/core.c:3722
 [<ffffffff812219f3>] autoremove_wake_function+0x13/0x90 kernel/sched/wait.c:281
 [<ffffffff81220736>] __wake_up_common+0xb6/0x150 kernel/sched/wait.c:73
 [<ffffffff81220804>] __wake_up+0x34/0x50 kernel/sched/wait.c:95
 [<ffffffff818a9970>] __jbd2_log_start_commit+0x200/0x250 fs/jbd2/journal.c:518
 [<ffffffff818a99ec>] jbd2_log_start_commit+0x2c/0x50 fs/jbd2/journal.c:537
 [<ffffffff818a9e3c>] jbd2_complete_transaction+0x18c/0x1c0 fs/jbd2/journal.c:749
 [<ffffffff8172f527>] ext4_sync_file+0x727/0x10a0 fs/ext4/fsync.c:150
 [<ffffffff8161abfc>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff8172d629>] generic_write_sync include/linux/fs.h:2607 [inline]
 [<ffffffff8172d629>] ext4_file_write_iter+0x7a9/0xd90 fs/ext4/file.c:169
 [<ffffffff8156f060>] new_sync_write fs/read_write.c:496 [inline]
 [<ffffffff8156f060>] __vfs_write+0x3e0/0x580 fs/read_write.c:509
 [<ffffffff81572e57>] vfs_write+0x187/0x530 fs/read_write.c:557
 [<ffffffff81576c89>] SYSC_write fs/read_write.c:604 [inline]
 [<ffffffff81576c89>] SyS_write+0xd9/0x1c0 fs/read_write.c:596
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fcc13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c