BTRFS info (device loop0): balance: start -d -m
BTRFS info (device loop0): relocating block group 6881280 flags data|metadata
BTRFS info (device loop0): relocating block group 5242880 flags data|metadata
------------[ cut here ]------------
ret == -ENOENT
WARNING: fs/btrfs/extent-tree.c:3418 at __btrfs_free_extent+0x1732/0x4570 fs/btrfs/extent-tree.c:3418, CPU#0: syz.0.0/5331
Modules linked in:
CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 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
RIP: 0010:__btrfs_free_extent+0x1732/0x4570 fs/btrfs/extent-tree.c:3418
Code: 03 00 00 e8 f0 99 db fd 4c 8b 7c 24 10 48 8b 5c 24 18 48 8b 44 24 30 4d 89 e5 49 bc 00 00 00 00 00 fc ff df e9 4e 0d 00 00 90 <0f> 0b 90 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 28 80 3c 01 00
RSP: 0018:ffffc900049feca0 EFLAGS: 00010246
RAX: 0000000000000002 RBX: ffff888033dcc510 RCX: 0000000000000005
RDX: ffffffff83ea27fe RSI: ffffffff8ef677e0 RDI: 00000000fffffffe
RBP: ffffc900049fee50 R08: ffff888000ac4a00 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000000 R12: 00000000fffffffe
R13: 00000000fffffffe R14: ffff8880126100b0 R15: 0000000000521000
FS:  00007f37247a86c0(0000) GS:ffff88808c87f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004000 CR3: 000000003370f000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 run_delayed_tree_ref fs/btrfs/extent-tree.c:1824 [inline]
 run_one_delayed_ref fs/btrfs/extent-tree.c:1851 [inline]
 btrfs_run_delayed_refs_for_head fs/btrfs/extent-tree.c:2058 [inline]
 __btrfs_run_delayed_refs+0x1870/0x4710 fs/btrfs/extent-tree.c:2133
 btrfs_run_delayed_refs+0xe6/0x3b0 fs/btrfs/extent-tree.c:2245
 btrfs_start_dirty_block_groups+0xd4c/0x10b0 fs/btrfs/block-group.c:3688
 btrfs_commit_transaction+0x38e/0x30e0 fs/btrfs/transaction.c:2292
 prepare_to_merge+0x931/0x19a0 fs/btrfs/relocation.c:1791
 relocate_block_group+0xbc1/0xe70 fs/btrfs/relocation.c:3636
 do_nonremap_reloc+0xa8/0x5b0 fs/btrfs/relocation.c:5268
 btrfs_relocate_block_group+0x7e6/0xc40 fs/btrfs/relocation.c:5434
 btrfs_relocate_chunk+0x115/0x820 fs/btrfs/volumes.c:3598
 __btrfs_balance+0x1db0/0x2ae0 fs/btrfs/volumes.c:4509
 btrfs_balance+0xaf3/0x11b0 fs/btrfs/volumes.c:4896
 btrfs_ioctl_balance+0x3d3/0x610 fs/btrfs/ioctl.c:3453
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f372399ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f37247a7fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3723c16090 RCX: 00007f372399ce59
RDX: 0000200000000180 RSI: 00000000c4009420 RDI: 0000000000000006
RBP: 00007f3723a32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3723c16128 R14: 00007f3723c16090 R15: 00007ffc4a15a418
 </TASK>