INFO: task syz-executor1:27250 blocked for more than 140 seconds.
      Not tainted 4.9.124-g6a1b592 #30
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D28744 27250  23486 0x00000004
 ffff880199b6c800 0000000000000000 ffff8801d95c6a00 ffff8801d9a6b000
 ffff8801db321c18 ffff8801c57c7750 ffffffff839f0afd ffffffff81237da7
 0000000000000000 ffff880199b6d0c0 0000000600000007 ffff8801db3224e8
Call Trace:
 [<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839fc524>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81eed8d8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839fb452>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839fb452>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff81599441>] inode_lock_shared include/linux/fs.h:776 [inline]
 [<ffffffff81599441>] lookup_slow+0x141/0x470 fs/namei.c:1645
 [<ffffffff815a5ac6>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a8426>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a8426>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815aded7>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815ae293>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815ae293>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff815f49b0>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff815f49b0>] path_listxattr+0xa0/0x140 fs/xattr.c:643
 [<ffffffff815f632a>] SYSC_listxattr fs/xattr.c:658 [inline]
 [<ffffffff815f632a>] SyS_listxattr+0x2a/0x40 fs/xattr.c:655
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a019d3>] 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: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3773:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor1/27235:
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff81599441>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff81599441>] lookup_slow+0x141/0x470 fs/namei.c:1645
1 lock held by syz-executor1/27250:
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff81599441>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff81599441>] lookup_slow+0x141/0x470 fs/namei.c:1645
1 lock held by syz-executor1/27275:
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff815e5ffc>] inode_lock include/linux/fs.h:766 [inline]
 #0:  (&sb->s_type->i_mutex_key#19){++++++}, at: [<ffffffff815e5ffc>] lock_mount+0x8c/0x2c0 fs/namespace.c:2101

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

NMI backtrace for cpu 0
CPU: 0 PID: 520 Comm: khungtaskd Not tainted 4.9.124-g6a1b592 #30
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8607d08 ffffffff81eb95e9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9fa0 ffff8801d8607d40
 ffffffff81ec4927 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec48ba>] 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
 [<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] 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 0xffffffff83a00606