INFO: task syz.4.154:6924 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.154       state:D stack:24696 pid:6924  tgid:6922  ppid:6386   task_flags:0x400140 flags:0x00080003
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x250
 drop_caches_sysctl_handler+0x97/0x170
 proc_sys_call_handler+0x4c8/0x830
 iter_file_splice_write+0x9a1/0x10f0
 direct_splice_actor+0x101/0x160
 splice_direct_to_actor+0x53a/0xc70
 do_splice_direct+0x195/0x290
 do_sendfile+0x535/0x7d0
 __se_sys_sendfile64+0xdf/0x1a0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2cb8d9cdd9
RSP: 002b:00007f2cb9b8e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f2cb9015fa0 RCX: 00007f2cb8d9cdd9
RDX: 0000200000002080 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007f2cb8e32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000023b R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2cb9016038 R14: 00007f2cb9015fa0 R15: 00007ffe8deb9698
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5435:
 #0: ffff888172e1e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034832e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
3 locks held by syz-executor/5623:
1 lock held by syz-executor/6856:
 #0: ffff88816ca4e0d8 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
2 locks held by syz.4.154/6924:
 #0: ffff888175206410 (sb_writers#3){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x160
 #1: ffff8881a7be00d8 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.368/8827:
 #0: ffff8881a7be00d8 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.0.370/8967:
 #0: ffff8881a7be00d8 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/9040:
 #0: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9040 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__lock_acquire+0x46/0x2cf0
Code: 24 e0 00 00 00 65 48 8b 05 bf 7a 97 11 48 89 44 24 08 31 ed 83 3d 69 34 8f 0e 00 0f 84 ef 13 00 00 45 89 cf 49 89 f9 48 8b 07 <48> 3d 80 03 fd 93 0f 84 da 13 00 00 41 89 cd 41 89 d6 8b 0d c2 f8
RSP: 0018:ffffc9000475f588 EFLAGS: 00000002
RAX: ffffffff8e94f0f8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e94f0f8
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff8e94f0f8
R10: dffffc0000000000 R11: fffffbfff1cfd250 R12: 0000000000000000
R13: ffffffff8e94f0f8 R14: 0000000000000001 R15: 0000000000000001
FS:  000055558fa72500(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe67844f6c CR3: 000000011d6aa000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 _raw_spin_lock+0x2e/0x40
 console_flush_all+0x67f/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 __ext4_msg+0x2b9/0x2d0
 ext4_put_super+0xb6/0xd80
 generic_shutdown_super+0x13d/0x2d0
 kill_block_super+0x44/0x90
 ext4_kill_sb+0x68/0xb0
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x437/0x4d0
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0xf3/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f12dbf9e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe67844f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f12dc032120 RCX: 00007f12dbf9e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe67845010
RBP: 00007ffe67845010 R08: 00007ffe67846010 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe678460a0
R13: 00007f12dc032120 R14: 0000000000046e47 R15: 00007ffe678460e0
 </TASK>
