INFO: task syz.6.1311:12840 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1311      state:D stack:28808 pid:12840 tgid:12839 ppid:12539  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6ba/0x920
 down_read+0x9c/0x330
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x120/0x240
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbfb199ce59
RSP: 002b:00007fbfb28d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fbfb1c15fa0 RCX: 00007fbfb199ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fbfb1c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbfb1c16038 R14: 00007fbfb1c15fa0 R15: 00007ffcc25caae8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5435:
 #0: ffff88810cbd60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900017782e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
2 locks held by syz-executor/10878:
2 locks held by syz-executor/12344:
1 lock held by syz.6.1311/12840:
 #0: ffff8881bdc2a0d8 (&type->s_umount_key#69){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/13117:
 #0: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
2 locks held by syz.2.1786/15705:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15692 Comm: syz.8.1782 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: 0033:0x7f01ea272050
Code: 74 08 48 89 48 08 48 83 c0 08 48 83 c2 08 48 39 d5 75 e7 48 8d 50 08 48 8b 04 24 48 29 c2 48 89 d5 48 c1 fd 03 e9 00 fc ff ff <4c> 89 e6 49 83 c4 08 48 89 0e 4c 39 e5 0f 85 4d ff ff ff e9 a3 fe
RSP: 002b:00007ffe83417410 EFLAGS: 00000246
RAX: 00007f01ea1d8d18 RBX: 00007f01eb145720 RCX: ffffffff8bae4e16
RDX: ffffffff8bae4e16 RSI: 00007f01ea1d8d18 RDI: 00007f01e9dff008
RBP: 00007f01ea1ff000 R08: 00007f01ea600000 R09: 00007f01ea616038
R10: 0000000000000003 R11: 0000000000000002 R12: 00007f01ea1d8d20
R13: 00007f01ea616038 R14: 00007f01e9dff008 R15: 0000000000000003
FS:  000055555e187500 GS:  0000000000000000
