syzbot
WARNING in __add_block_group_free_space
Status:
upstream: reported on 2026/08/10 00:34
Subsystems:
btrfs
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+6931616d57696102d8aa@syzkaller.appspotmail.com
First crash: 7d07h, last: 1d23h
Sample crash report:
------------[ cut here ]------------
btrfs_abort_should_print_stack(__error)
WARNING: fs/btrfs/free-space-tree.c:1440 at __add_block_group_free_space+0x5a3/0x5b0 fs/btrfs/free-space-tree.c:1440, CPU#0: kworker/u4:3/41
Modules linked in:
CPU: 0 UID: 0 PID: 41 Comm: kworker/u4:3 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:__add_block_group_free_space+0x5a3/0x5b0 fs/btrfs/free-space-tree.c:1440
Code: 07 38 c1 0f 8c ce fc ff ff 4c 89 f7 e8 76 bc 00 fe e9 c1 fc ff ff e8 1c 87 91 fd eb 10 e8 15 87 91 fd eb 09 e8 0e 87 91 fd 90 <0f> 0b 90 44 89 e1 f7 d9 e9 51 fe ff ff 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900004374b8 EFLAGS: 00010293
RAX: ffffffff84358aa2 RBX: ffff888051f9c001 RCX: ffff88801ae48000
RDX: 0000000000000000 RSI: ffffffff8f1f5b20 RDI: 00000000ffffffe4
RBP: ffff8880427b7490 R08: ffff88801ae48000 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: 00000000ffffffe4
R13: ffff8880501ea580 R14: ffff8880427b74f0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88808c549000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd5505fce9c CR3: 000000000e946000 CR4: 0000000000352ef0
Call Trace:
<TASK>
btrfs_add_block_group_free_space+0xd0/0x130 fs/btrfs/free-space-tree.c:1465
btrfs_create_pending_block_groups+0xcc6/0x15e0 fs/btrfs/block-group.c:2952
__btrfs_end_transaction+0x140/0x640 fs/btrfs/transaction.c:1092
flush_space+0x3e9/0xde0 fs/btrfs/space-info.c:912
do_async_reclaim_metadata_space+0x3e8/0x940 fs/btrfs/space-info.c:1211
btrfs_async_reclaim_metadata_space+0x89/0xe0 fs/btrfs/space-info.c:1278
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
* Struck through repros no longer work on HEAD.