------------[ cut here ]------------
BTRFS: Transaction aborted (error -28)
WARNING: fs/btrfs/block-group.c:4097 at do_chunk_alloc fs/btrfs/block-group.c:4097 [inline], CPU#0: kworker/u4:7/1042
WARNING: fs/btrfs/block-group.c:4097 at btrfs_chunk_alloc+0x101d/0x15e0 fs/btrfs/block-group.c:4338, CPU#0: kworker/u4:7/1042
Modules linked in:
CPU: 0 UID: 0 PID: 1042 Comm: kworker/u4:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events_unbound btrfs_async_reclaim_metadata_space
RIP: 0010:do_chunk_alloc fs/btrfs/block-group.c:4097 [inline]
RIP: 0010:btrfs_chunk_alloc+0x101f/0x15e0 fs/btrfs/block-group.c:4338
Code: 87 c2 b8 fd e9 6d 01 00 00 e8 cd d3 9d fd 84 c0 74 22 e8 74 c2 b8 fd e9 5a 01 00 00 e8 6a c2 b8 fd 48 8d 3d 63 06 0e 0c 89 de <67> 48 0f b9 3a e9 b3 fc ff ff e8 c2 b2 91 07 41 89 c6 31 ff 89 c6
RSP: 0018:ffffc9000127f6f0 EFLAGS: 00010293
RAX: ffffffff840bc526 RBX: ffffffffffffffe4 RCX: ffff888036640000
RDX: 0000000000000000 RSI: 00000000ffffffe4 RDI: ffffffff9019cb90
RBP: 0000000000000000 R08: ffff888036640000 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: 1ffff11006c9c416
R13: ffff888047dc0d18 R14: ffff888033794001 R15: ffff888036954000
FS:  0000000000000000(0000) GS:ffff88808cabd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa1d84de9c0 CR3: 000000000e54a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 flush_space+0x353/0xd30 fs/btrfs/space-info.c:896
 do_async_reclaim_metadata_space+0x3fc/0x960 fs/btrfs/space-info.c:1187
 btrfs_async_reclaim_metadata_space+0x89/0xe0 fs/btrfs/space-info.c:1254
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	87 c2                	xchg   %eax,%edx
   2:	b8 fd e9 6d 01       	mov    $0x16de9fd,%eax
   7:	00 00                	add    %al,(%rax)
   9:	e8 cd d3 9d fd       	call   0xfd9dd3db
   e:	84 c0                	test   %al,%al
  10:	74 22                	je     0x34
  12:	e8 74 c2 b8 fd       	call   0xfdb8c28b
  17:	e9 5a 01 00 00       	jmp    0x176
  1c:	e8 6a c2 b8 fd       	call   0xfdb8c28b
  21:	48 8d 3d 63 06 0e 0c 	lea    0xc0e0663(%rip),%rdi        # 0xc0e068b
  28:	89 de                	mov    %ebx,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 b3 fc ff ff       	jmp    0xfffffce7
  34:	e8 c2 b2 91 07       	call   0x791b2fb
  39:	41 89 c6             	mov    %eax,%r14d
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 c6                	mov    %eax,%esi