INFO: task syz.3.115:6669 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.115       state:D stack:21888 pid:6669  tgid:6668  ppid:6094   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feea9b9cdd9
RSP: 002b:00007feeaaabd028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007feea9e15fa0 RCX: 00007feea9b9cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007feea9e15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feea9e16038 R14: 00007feea9e15fa0 R15: 00007fff36803988
 </TASK>
INFO: task syz.4.136:6831 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.136       state:D stack:26240 pid:6831  tgid:6830  ppid:6616   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x3a7/0x9e0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0c139cdd9
RSP: 002b:00007fd0c22fa028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fd0c1615fa0 RCX: 00007fd0c139cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 00007fd0c1432d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd0c1616038 R14: 00007fd0c1615fa0 R15: 00007ffea8314c08
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5638:
 #0: ffff888178f3b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by syz-executor/5811:
3 locks held by kworker/1:4/5862:
 #0: ffff88810006b148 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0
 #1: ffffc9000680fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0
 #2: ffff88816b7d9240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
1 lock held by syz.3.115/6669:
 #0: ffff88810f2de0e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.4.136/6831:
 #0: ffff88810f2de0e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.2.442/8810:
 #0: ffff88810f2de0e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/8927:
 #0: ffffffff8e7648f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
2 locks held by syz.6.591/9770:
2 locks held by rm/9802:

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

NMI backtrace for cpu 1
CPU: 1 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/0x300
 sys_info+0x135/0x170
 watchdog+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 3 Comm: pool_workqueue_ 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:zap_class+0xcf/0x340
Code: 49 81 fc 00 00 08 00 0f 84 a4 01 00 00 4e 8b 2c e5 40 64 e0 93 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 75 00 <41> f6 c6 fc 0f 84 e1 00 00 00 41 c1 ee 08 4a 8d 1c 75 10 64 25 93
RSP: 0018:ffffc90000087c50 EFLAGS: 00000093
RAX: 000000000004deec RBX: ffffffff932f21e8 RCX: 000000000004dee9
RDX: ffffffff93e06438 RSI: 0000000000000002 RDI: 0000000000059c3a
RBP: ffffffff942468b0 R08: ffffffff81af1268 R09: ffffffff8e75e5e0
R10: dffffc0000000000 R11: fffffbfff2023997 R12: 000000000005a2cf
R13: ffffffff942c1e10 R14: 0000000000eeb914 R15: 0000000000000cdd
FS:  0000000000000000(0000) GS:ffff88818de57000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff89c85e70 CR3: 00000001057d6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lockdep_unregister_key+0x1c3/0x350
 pwq_release_workfn+0x6ea/0x880
 kthread_worker_fn+0x509/0xb70
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
