syzbot


WARNING in nilfs_cpfile_delete_checkpoints

Status: upstream: reported C repro on 2026/07/06 06:10
Subsystems: nilfs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+79b815da3aec0a6a4d02@syzkaller.appspotmail.com
First crash: 7d19h, last: 5d14h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
22dd8efc-9214-4fd2-bb27-7e89d4ec16b8 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in nilfs_cpfile_delete_checkpoints 2026/07/04 00:00 2026/07/04 00:00 2026/07/04 00:46 93f579545ae410f5bccfa141d2e7bf03178f036c

			
		
Discussions (3)
Title Replies (including bot) Last reply
[PATCH] nilfs2: handle corrupted checkpoint count gracefully during deletion 2 (2) 2026/07/07 18:16
[PATCH] nilfs2: handle corrupted checkpoint count gracefully during deletion 2 (2) 2026/07/06 16:39
[syzbot] [nilfs?] WARNING in nilfs_cpfile_delete_checkpoints 0 (1) 2026/07/06 06:10

Sample crash report:
------------[ 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>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/04 11:35 upstream 71dfdfb0209b fcece630 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] [mounted in repro #3 (clean fs)] ci-snapshot-upstream-root WARNING in nilfs_cpfile_delete_checkpoints
2026/07/04 09:25 upstream 71dfdfb0209b fcece630 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nilfs_cpfile_delete_checkpoints
2026/07/02 06:05 upstream 4a50a141f05a 27192279 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in nilfs_cpfile_delete_checkpoints
* Struck through repros no longer work on HEAD.