[v6.6] kernel BUG in _ocfs2_free_suballoc_bits

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0a40c6fbd105 Linux 6.6.141
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17844e1f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=5530932ac2240abe5cb3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1702b61f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bef5f7e53495/disk-0a40c6fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/61ce39aaab25/vmlinux-0a40c6fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43d2363e7871/bzImage-0a40c6fb.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/4ba5ccfa0301/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=16d86aa6580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+553093...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ocfs2/suballoc.c:2478!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5894 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:_ocfs2_free_suballoc_bits+0xdca/0x1080 fs/ocfs2/suballoc.c:2478
Code: c2 0f 8c 82 fa ff ff 4c 89 e7 49 89 ce 45 89 c7 e8 cb 33 7d fe 45 89 f8 4c 89 f1 4c 8b 74 24 28 e9 64 fa ff ff e8 a6 f4 24 fe <0f> 0b e8 9f f4 24 fe 0f 0b 65 44 8b 25 71 7e a1 7c bf 07 00 00 00
RSP: 0018:ffffc900033276a0 EFLAGS: 00010293
RAX: ffffffff8362374a RBX: 0000000000000001 RCX: ffff8880237a0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003327828 R08: 0000000000000020 R09: 00000000000000fc
R10: dffffc0000000000 R11: fffffbfff1d1675e R12: dffffc0000000000
R13: ffff88805bfcfe00 R14: 00000000000000fc R15: 0000000000000020
FS: 000055557ae42500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555572b7ba38 CR3: 00000000618fe000 CR4: 00000000003506e0
Call Trace:
<TASK>
_ocfs2_free_clusters+0x5e5/0xa70 fs/ocfs2/suballoc.c:2579
ocfs2_sync_local_to_main+0x527/0xb90 fs/ocfs2/localalloc.c:996
ocfs2_shutdown_local_alloc+0x729/0xaa0 fs/ocfs2/localalloc.c:446
ocfs2_dismount_volume+0x1e5/0x8a0 fs/ocfs2/super.c:1881
generic_shutdown_super+0x134/0x2b0 fs/super.c:693
kill_block_super+0x44/0x90 fs/super.c:1660
deactivate_locked_super+0x97/0x100 fs/super.c:481
cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259
task_work_run+0x1d4/0x260 kernel/task_work.c:245
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc3ebb9e097
Code: a2 c7 05 5c 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff83b9e658 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc3ebc321ca RCX: 00007fc3ebb9e097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff83b9e710
RBP: 00007fff83b9e710 R08: 00007fff83b9f710 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff83b9f7a0
R13: 00007fc3ebc321ca R14: 0000000000029b17 R15: 00007fff83b9f7e0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:_ocfs2_free_suballoc_bits+0xdca/0x1080 fs/ocfs2/suballoc.c:2478
Code: c2 0f 8c 82 fa ff ff 4c 89 e7 49 89 ce 45 89 c7 e8 cb 33 7d fe 45 89 f8 4c 89 f1 4c 8b 74 24 28 e9 64 fa ff ff e8 a6 f4 24 fe <0f> 0b e8 9f f4 24 fe 0f 0b 65 44 8b 25 71 7e a1 7c bf 07 00 00 00
RSP: 0018:ffffc900033276a0 EFLAGS: 00010293
RAX: ffffffff8362374a RBX: 0000000000000001 RCX: ffff8880237a0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003327828 R08: 0000000000000020 R09: 00000000000000fc
R10: dffffc0000000000 R11: fffffbfff1d1675e R12: dffffc0000000000
R13: ffff88805bfcfe00 R14: 00000000000000fc R15: 0000000000000020
FS: 000055557ae42500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff5933f4000 CR3: 00000000618fe000 CR4: 00000000003506e0


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