INFO: task syz-executor4:13072 blocked for more than 140 seconds.
      Not tainted 4.9.118-g47b77b8 #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D27976 13072   3876 0x00000004
 ffff88019df73000 ffff8801bc0caf40 ffff8801b5aea4c0 ffff8801b8338000
 ffff8801db221c18 ffff8801a6fb7660 ffffffff839ebbad dffffc0000000000
 ffff8801d5d8cc10 ffff8801a6fb7620 00ff88019df738c0 ffff8801db2224e8
Call Trace:
 [<ffffffff839ed1af>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff815c80a2>] d_wait_lookup fs/dcache.c:2455 [inline]
 [<ffffffff815c80a2>] d_alloc_parallel+0xeb2/0x17c0 fs/dcache.c:2537
 [<ffffffff8159505c>] lookup_slow+0x19c/0x470 fs/namei.c:1650
 [<ffffffff815a1686>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3fe6>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a3fe6>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a9a97>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9e53>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9e53>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff8161c10f>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff8161c10f>] do_utimes+0x17f/0x2c0 fs/utimes.c:155
 [<ffffffff8161c7ed>] SYSC_futimesat fs/utimes.c:214 [inline]
 [<ffffffff8161c7ed>] SyS_futimesat fs/utimes.c:189 [inline]
 [<ffffffff8161c7ed>] SYSC_utimes fs/utimes.c:220 [inline]
 [<ffffffff8161c7ed>] SyS_utimes+0x13d/0x1b0 fs/utimes.c:217
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fca93>] 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: [<ffffffff8136679c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136679c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff81425fb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3676:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d853c>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157301e>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157301e>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3774:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fac52>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821207a2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor4/13017:
 #0:  (&sb->s_type->i_mutex_key#16){++++++}, at: [<ffffffff81595001>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#16){++++++}, at: [<ffffffff81595001>] lookup_slow+0x141/0x470 fs/namei.c:1645
1 lock held by syz-executor4/13070:
 #0:  (&type->s_umount_key#36/1){+.+.+.}, at: [<ffffffff8157bd42>] alloc_super fs/super.c:241 [inline]
 #0:  (&type->s_umount_key#36/1){+.+.+.}, at: [<ffffffff8157bd42>] sget_userns+0x552/0xba0 fs/super.c:503
1 lock held by syz-executor4/13072:
 #0:  (&sb->s_type->i_mutex_key#16){++++++}, at: [<ffffffff81595001>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#16){++++++}, at: [<ffffffff81595001>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.118-g47b77b8 #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d86d7d08 ffffffff81eb4b89 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d86d7d40
 ffffffff81ebfe87 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4b89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4b89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfe87>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe1a>] 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
 [<ffffffff81366d34>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d34>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d34>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d34>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fcc5c>] 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 0xffffffff839fb6b6