[syzbot] [nilfs?] WARNING in nilfs_cpfile_delete_checkpoints

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 71dfdfb0209b Merge tag 'vfs-7.2-rc2.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10c00d39580000
kernel config: https://syzkaller.appspot.com/x/.config?x=20c9876b0f77b546
dashboard link: https://syzkaller.appspot.com/bug?extid=79b815da3aec0a6a4d02
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14d01c6e580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12776e6e580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-71dfdfb0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/522f1a761fe1/vmlinux-71dfdfb0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/595943c8baaa/bzImage-71dfdfb0.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/e2143050dc41/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/958ab3f4c7bb/mount_5.gz
mounted in repro #3: https://storage.googleapis.com/syzbot-assets/77f82daa3be0/mount_6.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=15143946580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+79b815...@syzkaller.appspotmail.com

------------[ cut here ]------------
le32_to_cpu(cp->cp_checkpoints_count) < n
WARNING: fs/nilfs2/cpfile.c:94 at nilfs_cpfile_block_sub_valid_checkpoints fs/nilfs2/cpfile.c:94 [inline], CPU#0: syz.0.17/5467
WARNING: fs/nilfs2/cpfile.c:94 at nilfs_cpfile_delete_checkpoints+0x913/0xce0 fs/nilfs2/cpfile.c:522, CPU#0: syz.0.17/5467
Modules linked in:
CPU: 0 UID: 0 PID: 5467 Comm: syz.0.17 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:nilfs_cpfile_block_sub_valid_checkpoints fs/nilfs2/cpfile.c:94 [inline]
RIP: 0010:nilfs_cpfile_delete_checkpoints+0x913/0xce0 fs/nilfs2/cpfile.c:522
Code: fb ff 41 89 c6 31 ff 89 c6 e8 e9 f9 f1 fd 45 85 f6 0f 85 6a 03 00 00 e8 9b f5 f1 fd 45 31 f6 e9 23 fd ff ff e8 8e f5 f1 fd 90 <0f> 0b 90 e9 d0 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 0a f9
RSP: 0018:ffffc900025df4e0 EFLAGS: 00010293
RAX: ffffffff83d48d02 RBX: 1ffff11006feb480 RCX: ffff88803462a540
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: ffffc900025df630 R08: ffffea0000dfd687 R09: 1ffffd40001bfad0
R10: dffffc0000000000 R11: fffff940001bfad1 R12: 0000000000000005
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888037f5a404
FS: 0000555559731500(0000) GS:ffff88808c54e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000044683000 CR4: 0000000000352ef0
Call Trace:
<TASK>
nilfs_ioctl_delete_checkpoints fs/nilfs2/ioctl.c:680 [inline]
nilfs_ioctl_prepare_clean_segments+0x158/0x840 fs/nilfs2/ioctl.c:787
nilfs_clean_segments+0x2b6/0xbb0 fs/nilfs2/segment.c:2546
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline]
nilfs_ioctl+0x2619/0x2780 fs/nilfs2/ioctl.c:1352
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+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff42779de59
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:00007ffd20bf4538 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff427a25fa0 RCX: 00007ff42779de59
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000009
RBP: 00007ff427833e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff427a25fac R14: 00007ff427a25fa0 R15: 00007ff427a25fa0
</TASK>


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