INFO: task syz.2.203:7923 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.203       state:D stack:24664 pid:7923  tgid:7921  ppid:7511   task_flags:0x400140 flags:0x00080002
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
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x540/0x9e0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f51bf79cdd9
RSP: 002b:00007f51c073d028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f51bfa15fa0 RCX: 00007f51bf79cdd9
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffff80000601
RBP: 00007f51bf832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000025a40 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f51bfa16038 R14: 00007f51bfa15fa0 R15: 00007ffdb84012d8
 </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
3 locks held by kworker/1:3/5083:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900017dfc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff888168a55250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0
2 locks held by getty/5436:
 #0: ffff888175e890a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
3 locks held by syz-executor/5616:
1 lock held by syz.2.203/7923:
 #0: ffff888109dee0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.9.482/10609:
 #0: ffff888109dee0d8 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz-executor/10885:
 #0: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
1 lock held by syz-executor/11162:
 #0: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770

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

NMI backtrace for cpu 0
CPU: 0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11162 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:rcu_is_watching+0x5a/0xb0
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 7c 25 86 00 48 c7 c3 d8 69 3a 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d 19 56 8e 11 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc90004f9f470 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff88823c6339d8 RCX: 0000000080000001
RDX: ffffc90004f9f601 RSI: ffffffff8c28af40 RDI: ffffffff8c28af00
RBP: dffffc0000000000 R08: ffffc90004f9f618 R09: 0000000000000000
R10: ffffc90004f9f678 R11: fffff520009f3ed1 R12: ffffc90004f9f628
R13: ffffffff8176f256 R14: ffffffff8e265798 R15: dffffc0000000000
FS:  00005555730b9500(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d8d45ca131 CR3: 000000010ef4c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_release+0x4b/0x3c0
 unwind_next_frame+0x1bba/0x2550
 __unwind_start+0x5b8/0x760
 arch_stack_walk+0xe3/0x150
 stack_trace_save+0xa9/0x100
 save_stack+0x122/0x230
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc7/0xd30
 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/0x840
 exit_to_user_mode_loop+0x8c/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa90ab5d60e
Code: Unable to access opcode bytes at 0x7fa90ab5d5e4.
RSP: 002b:00007fffd4464d58 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: 0000000000000020 RBX: 00005555730b9500 RCX: 00007fa90ab5d60e
RDX: 0000000000000020 RSI: 00007fa90b944670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007fffd4464dd4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fa90b944670 R15: 0000000000000000
 </TASK>
