INFO: task syz.8.837:12975 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.837       state:D stack:21848 pid:12975 tgid:12974 ppid:12468  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 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
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efd8c59cdd9
RSP: 002b:00007efd8d4b6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007efd8c815fa0 RCX: 00007efd8c59cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007efd8c815fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd8c816038 R14: 00007efd8c815fa0 R15: 00007ffd231a90a8
 </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/5439:
 #0: ffff8881114a00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
6 locks held by kworker/u8:4/5674:
3 locks held by syz-executor/10121:
1 lock held by syz.8.837/12975:
 #0: ffff88810a7e80d8 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.1.975/14005:
 #0: ffff88810a7e80d8 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.7.1145/15019:
 #0: ffff88810a7e80d8 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
2 locks held by syz-executor/15671:
 #0: ffff88811210e0d8 (&type->s_umount_key#80){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by syz.8.1295/16073:
2 locks held by modprobe/16084:
 #0: ffff88823c63aea0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150
 #1: ffff88823c624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880

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

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: 16073 Comm: syz.8.1295 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:__page_table_check_zero+0x20c/0x3e0
Code: 89 ff 85 ed 0f 85 db 01 00 00 48 83 c3 04 48 89 df be 04 00 00 00 e8 d3 74 f4 ff 48 89 d8 48 c1 e8 03 4c 89 f5 42 0f b6 04 30 <84> c0 0f 85 c5 00 00 00 8b 1b 31 ff 89 de e8 81 3b 89 ff 85 db 0f
RSP: 0018:ffffc900042ef878 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffff8881621f170c RCX: ffffffff823c74cd
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881621f170c
RBP: dffffc0000000000 R08: ffff8881621f170f R09: 1ffff1102c43e2e1
R10: dffffc0000000000 R11: ffffed102c43e2e2 R12: 0000000000000000
R13: 000000000019e37d R14: dffffc0000000000 R15: ffff8881621f16c0
FS:  00007f3933bca6c0(0000) GS:ffff88818dc90000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7cfabea4c0 CR3: 000000011c76a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __free_frozen_pages+0xbd7/0xd30
 vfree+0x1d1/0x2f0
 kcov_close+0x28/0x50
 __fput+0x44f/0xa60
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x22c0
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 exit_to_user_mode_loop+0x86/0x480
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3932d9cdd9
Code: Unable to access opcode bytes at 0x7f3932d9cdaf.
RSP: 002b:00007f3933bca028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 00007f3933015fa0 RCX: 00007f3932d9cdd9
RDX: 0000000000002020 RSI: 00002000000021c0 RDI: 0000000000000005
RBP: 00007f3932e32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3933016038 R14: 00007f3933015fa0 R15: 00007ffc91fd02b8
 </TASK>
