------------[ cut here ]------------
BTRFS: Transaction aborted (error -28)
WARNING: fs/btrfs/block-group.c:4105 at do_chunk_alloc fs/btrfs/block-group.c:4105 [inline], CPU#0: kworker/u4:2/27
WARNING: fs/btrfs/block-group.c:4105 at btrfs_chunk_alloc+0x101d/0x15e0 fs/btrfs/block-group.c:4346, CPU#0: kworker/u4:2/27
Modules linked in:
CPU: 0 UID: 0 PID: 27 Comm: kworker/u4:2 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:4105 [inline]
RIP: 0010:btrfs_chunk_alloc+0x101f/0x15e0 fs/btrfs/block-group.c:4346
Code: 87 96 b1 fd e9 6d 01 00 00 e8 3d 9a 96 fd 84 c0 74 22 e8 74 96 b1 fd e9 5a 01 00 00 e8 6a 96 b1 fd 48 8d 3d 23 4c 07 0c 89 de <67> 48 0f b9 3a e9 b3 fc ff ff e8 d2 3e 9c 07 41 89 c6 31 ff 89 c6
RSP: 0018:ffffc900003576d0 EFLAGS: 00010293
RAX: ffffffff84141916 RBX: ffffffffffffffe4 RCX: ffff88801c72a4c0
RDX: 0000000000000000 RSI: 00000000ffffffe4 RDI: ffffffff901b6540
RBP: 0000000000000000 R08: ffff88801c72a4c0 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: 1ffff11006dab516
R13: ffff888047a943d8 R14: ffff88803f470001 R15: ffff888042e57800
FS:  0000000000000000(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6213a4c000 CR3: 00000000119d8000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 flush_space+0x353/0xd80 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:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 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 96 b1 fd e9 6d    	xchg   %edx,0x6de9fdb1(%rsi)
   6:	01 00                	add    %eax,(%rax)
   8:	00 e8                	add    %ch,%al
   a:	3d 9a 96 fd 84       	cmp    $0x84fd969a,%eax
   f:	c0 74 22 e8 74       	shlb   $0x74,-0x18(%rdx,%riz,1)
  14:	96                   	xchg   %eax,%esi
  15:	b1 fd                	mov    $0xfd,%cl
  17:	e9 5a 01 00 00       	jmp    0x176
  1c:	e8 6a 96 b1 fd       	call   0xfdb1968b
  21:	48 8d 3d 23 4c 07 0c 	lea    0xc074c23(%rip),%rdi        # 0xc074c4b
  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 d2 3e 9c 07       	call   0x79c3f0b
  39:	41 89 c6             	mov    %eax,%r14d
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 c6                	mov    %eax,%esi