INFO: task syz.1.622:9170 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.622       state:D stack:25336 pid:9170  tgid:9169  ppid:8865   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14bc/0x5000
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x99/0x2e0
 super_lock+0x2a9/0x3b0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x4da/0x950
 do_syscall_64+0xfa/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7ad7f8f7c9
RSP: 002b:00007f7ad61ee038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f7ad81e5fa0 RCX: 00007f7ad7f8f7c9
RDX: 000000003a736e6f RSI: 00002000000002c0 RDI: ffffffff80000700
RBP: 00007f7ad7ff297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ad81e6038 R14: 00007f7ad81e5fa0 R15: 00007ffea8dbea38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5654:
 #0: ffff88817566c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460
3 locks held by syz-executor/5829:
1 lock held by syz.1.622/9170:
 #0: ffff888114f720e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.2.1047/11443:
 #0: ffff888114f720e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.1.1099/11709:
 #0: ffff888114f720e0 (&type->s_umount_key#59){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/11772:
 #0: ffff8881a384e0e0 (&type->s_umount_key#65){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
1 lock held by syz.8.1145/12403:
3 locks held by syz.5.1147/12418:

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf95/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x599/0xb30
 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: 12402 Comm: syz.8.1145 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+0x1969/0x2cf0
Code: 89 c1 81 e1 ff 0f 00 00 89 0d 97 86 e8 13 2b 05 8d 86 e8 13 25 ff 0f 00 00 39 05 4e 86 e7 11 73 06 89 05 46 86 e7 11 48 8b 02 <48> 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 4c 39 e8
RSP: 0018:ffffc90007a1f4c8 EFLAGS: 00000002
RAX: ffffffff9328bf38 RBX: 0000000000000144 RCX: 0000000000000007
RDX: ffffffff962dfcb8 RSI: ffff888171ba8b80 RDI: 0000000000000144
RBP: afb58ab00a22f2ac R08: ffffc90007a1f490 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff819ee660 R12: ffffffff9611a3e8
R13: ffffffff9328bf38 R14: ffff888171ba8000 R15: 0000000000000006
FS:  00005555810da500(0000) GS:ffff8882a9e3a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33ef7ff8 CR3: 00000001748a8000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x117/0x340
 _raw_spin_lock+0x2e/0x40
 console_flush_all+0x6ab/0xb60
 console_unlock+0xbb/0x190
 vprintk_emit+0x4f8/0x5f0
 _printk+0xcf/0x120
 __dynamic_pr_debug+0x168/0x1f0
 free_basic_memory_bitmaps+0x201/0x260
 snapshot_release+0xe4/0x1d0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xff/0x4f0
 do_syscall_64+0x2e3/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff1698f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff6d5281f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000005e0ee RCX: 00007eff1698f7c9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007eff16be7da0 R08: 0000000000000001 R09: 0000001b6d5284ef
R10: 0000001b32f20000 R11: 0000000000000246 R12: 00007eff16be5fac
R13: 00007eff16be5fa0 R14: ffffffffffffffff R15: 00007fff6d528310
 </TASK>
