I get the following call trace about 0.6s after dnf completes an
update which I imagine deletes many files. I'll try to reproduce and
get /proc/lock_stat

[   95.674507] kernel: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
[   95.676537] kernel: turning off the locking correctness validator.
[   95.676537] kernel: Please attach the output of /proc/lock_stat to
the bug report
[   95.676538] kernel: CPU: 5 PID: 6045 Comm: systemd Not tainted
5.14.0-0.rc5.42.fc35.x86_64+debug #1
[   95.676540] kernel: Hardware name: LENOVO 20QDS3E200/20QDS3E200,
BIOS N2HET63W (1.46 ) 06/01/2021
[   95.681911] kernel: Call Trace:
[   95.681913] kernel:  dump_stack_lvl+0x57/0x72
[   95.681919] kernel:  __lock_acquire.cold+0x11/0x2b8
[   95.681923] kernel:  lock_acquire+0xc4/0x2e0
[   95.681926] kernel:  ? block_group_cache_tree_search+0x24/0x110
[   95.681929] kernel:  ? rcu_read_lock_sched_held+0x3f/0x80
[   95.681931] kernel:  ? check_ref_cleanup+0x154/0x160
[   95.681933] kernel:  ? kmem_cache_free+0x2c7/0x380
[   95.681936] kernel:  ? __mutex_unlock_slowpath+0x35/0x270
[   95.681940] kernel:  _raw_spin_lock+0x31/0x80
[   95.681941] kernel:  ? block_group_cache_tree_search+0x24/0x110
[   95.681943] kernel:  block_group_cache_tree_search+0x24/0x110
[   95.681944] kernel:  btrfs_free_tree_block+0x126/0x300
[   95.681947] kernel:  __btrfs_cow_block+0x308/0x5d0
[   95.681950] kernel:  btrfs_cow_block+0xf8/0x220
[   95.681951] kernel:  btrfs_search_slot+0x508/0x9e0
[   95.681954] kernel:  btrfs_lookup_dir_item+0x6c/0xb0
[   95.681956] kernel:  __btrfs_unlink_inode+0x9a/0x4e0
[   95.681960] kernel:  btrfs_rmdir+0xdf/0x1d0
[   95.681962] kernel:  vfs_rmdir+0x7e/0x190
[   95.681965] kernel:  do_rmdir+0x16a/0x190
[   95.681967] kernel:  do_syscall_64+0x38/0x90
[   95.681970] kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   95.681972] kernel: RIP: 0033:0x7f07bfcb3e8b
[   95.681975] kernel: Code: 73 01 c3 48 8b 0d ed ff 0c 00 f7 d8 64 89
01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 07
01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d bd ff 0c 00 f7 d8
64 89 01 48
[   95.681976] kernel: RSP: 002b:00007f07be6647a8 EFLAGS: 00000246
ORIG_RAX: 0000000000000107
[   95.681978] kernel: RAX: ffffffffffffffda RBX: 0000000000000006
RCX: 00007f07bfcb3e8b
[   95.681979] kernel: RDX: 0000000000000200 RSI: 00007f07b0000bd3
RDI: 0000000000000026
[   95.681980] kernel: RBP: 0000000000000026 R08: 0000000000000000
R09: 00007f07b0000080
[   95.681980] kernel: R10: 0000000000000078 R11: 0000000000000246
R12: 0000000000000000
[   95.681981] kernel: R13: 00007f07b0000bd3 R14: 0000000000000200
R15: 00007f07be6653f8

mount options:
/dev/nvme0n1p5 on / type btrfs
(rw,noatime,seclabel,compress=zstd:1,ssd,space_cache=v2,subvolid=268,subvol=/root34)

features:
csum_type        1 (xxhash64)
num_devices        1
compat_flags        0x0
compat_ro_flags        0x3
            ( FREE_SPACE_TREE |
              FREE_SPACE_TREE_VALID )
incompat_flags        0x355
            ( MIXED_BACKREF |
              MIXED_GROUPS |
              COMPRESS_ZSTD |
              EXTENDED_IREF |
              SKINNY_METADATA |
              NO_HOLES )

Full dmesg:
https://drive.google.com/file/d/1cLuWfvM_K4E6ML44KgAbNljF16bT3nSi/view?usp=sharing

-- 
Chris Murphy