INFO: task syz.8.2281:15665 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.2281      state:D stack:24776 pid:15665 tgid:15664 ppid:14953  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x87d/0x1080
 down_write+0x1bc/0x200
 super_lock+0x289/0x3d0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x538/0x9a0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f757619ce59
RSP: 002b:00007f7576fb6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f7576415fa0 RCX: 00007f757619ce59
RDX: 0000000000000000 RSI: 0000200000000100 RDI: ffffffff80000301
RBP: 00007f7576232e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7576416038 R14: 00007f7576415fa0 R15: 00007ffd1d1419a8
 </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
5 locks held by kworker/u9:5/3351:
2 locks held by getty/5438:
 #0: ffff88816f6010a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
2 locks held by syz-executor/8104:
1 lock held by syz.8.2281/15665:
 #0: ffff8881110fa0d8 (&type->s_umount_key#82){++++}-{4:4}, at: super_lock+0x289/0x3d0
1 lock held by syz.8.2769/18998:
 #0: ffff8881110fa0d8 (&type->s_umount_key#82){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
2 locks held by syz.0.2783/19074:
6 locks held by syz.1.2784/19072:

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

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: 144 Comm: kworker/u10:5 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
Workqueue: events_unbound btrfs_async_reclaim_metadata_space
RIP: 0010:__lock_acquire+0x1727/0x2cf0
Code: 05 26 cc a6 14 48 b8 00 00 00 00 01 00 00 00 48 89 05 0d cc a6 14 48 8d 84 24 90 00 00 00 48 89 05 fe 4b a6 14 31 ff 45 31 ff <4d> 85 ff 4c 8b 6c 24 08 74 2e 49 8b 47 30 48 85 c0 74 25 48 8b 40
RSP: 0018:ffffc900031eebb0 EFLAGS: 00000046
RAX: ffffffff93f005a8 RBX: 00000000000003cc RCX: 000000000009b516
RDX: ffffffff96fcbdc8 RSI: ffff888169e8c7e8 RDI: 00000000000003cc
RBP: 12f300c07ec4d4dd R08: ffffc900031eeb78 R09: 0000000000000020
R10: 0000000000000000 R11: ffffffff81a28190 R12: 0000000000000012
R13: ffff888169e8c7e8 R14: ffff888169e8bb80 R15: ffffffff96de8578
FS:  0000000000000000(0000) GS:ffff8882a921d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8903abed58 CR3: 00000001be33c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 seqcount_lockdep_reader_access+0x75/0xc0
 bad_range+0x8e/0x2a0
 get_page_from_freelist+0x21e5/0x2270
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x79/0x5e0
 refill_objects+0x2d5/0x350
 __pcs_replace_empty_main+0x2bf/0x6b0
 kmem_cache_alloc_noprof+0x382/0x5f0
 alloc_extent_state+0x22/0x2e0
 btrfs_convert_extent_bit+0x120/0x17c0
 btrfs_write_marked_extents+0x15c/0x300
 btrfs_write_and_wait_transaction+0x107/0x240
 btrfs_commit_transaction+0x1db7/0x30b0
 flush_space+0x28a/0xde0
 do_async_reclaim_metadata_space+0x3e8/0x940
 btrfs_async_reclaim_metadata_space+0x89/0xe0
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
