WARNING in nilfs_rmdir (3)

Status: upstream: reported C repro on 2026/09/28 21:44
Subsystems: nilfs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+c388db0347b7fc88fa7a@syzkaller.appspotmail.com
First crash: 15d, last: 4d11h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
c8b9e4ef repro-c Reproduced: ✅ ❓ WARNING in nilfs_rmdir (3) 2026/10/05 14:45 2026/10/05 14:45 2026/10/05 18:10 1995e6c7
bd10f679 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in nilfs_rmdir (3) 2026/09/26 01:03 2026/09/26 01:03 2026/09/26 01:33 f281d9d2
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] nilfs2: fix link count underflow when removing corrupted directory 2 (2) 2026/10/06 17:05
[syzbot] [nilfs?] WARNING in nilfs_rmdir (3) 1 (4) 2026/10/06 08:03
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING in nilfs_rmdir -1 syz, C done 42 657d 680d 3/3 fixed on 2025/01/28 12:20
upstream WARNING in nilfs_rmdir (2) prio:low nilfs -1 1 199d 195d 0/29 auto-obsoleted due to no activity on 2026/07/02 20:36
linux-5.15 WARNING in nilfs_rmdir origin:lts-only -1 syz, C done 4 656d 664d 3/3 fixed on 2025/01/30 02:24
upstream WARNING in nilfs_rmdir nilfs -1 syz, C error 295 641d 688d 28/29 fixed on 2025/05/06 15:33
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2026/10/06 07:46 14m konishi.ryusuke@gmail.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a90ee4305c4a OK job log log
2026/10/05 19:34 16m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 67f0943b394d920b6c142aad8c6af94340342ae7 report job log log

Sample crash report:
NILFS (loop0): broken superblock, retrying with spare superblock (blocksize = 1024)
NILFS (loop0): broken superblock, retrying with spare superblock (blocksize = 4096)
------------[ cut here ]------------
inode->i_nlink == 0
WARNING: fs/inode.c:408 at drop_nlink+0xc5/0x110 fs/inode.c:408, CPU#1: syz-executor166/5936
Modules linked in:
CPU: 1 UID: 0 PID: 5936 Comm: syz-executor166 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:drop_nlink+0xc5/0x110 fs/inode.c:408
Code: 50 09 00 00 be 08 00 00 00 e8 e7 45 e9 ff f0 48 ff 83 50 09 00 00 5b 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc e8 bc 47 7d ff 90 <0f> 0b 90 eb 81 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 5b ff ff ff
RSP: 0018:ffffc9000392fc70 EFLAGS: 00010293
RAX: ffffffff82498df4 RBX: ffff88805e9c9558 RCX: ffff888032d7ddc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100535792b R12: 1ffff1100bd392b4
R13: ffff88805e9c9558 R14: ffff88805e9c95a0 R15: dffffc0000000000
FS:  000055555fff0400(0000) GS:ffff888125cc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb871d39286 CR3: 00000000361f2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nilfs_rmdir+0x1b4/0x250 fs/nilfs2/namei.c:347
 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5515
 filename_rmdir+0x292/0x520 fs/namei.c:5572
 __do_sys_rmdir fs/namei.c:5595 [inline]
 __se_sys_rmdir+0x2e/0x140 fs/namei.c:5592
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f87bafa97
Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 4a 07 02 00 48 83 c4 18 c3 0f 1f 44 00 00 b8 54 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 d8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd6579c7f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8f87bafa97
RDX: 0000000000000000 RSI: 00007f8f87c393a3 RDI: 00007f8f87c0cc45
RBP: 00007f8f87c0cbee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffd6579c800
R13: 0000000000000000 R14: 00007f8f87c34cc0 R15: 0000000000000002
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/05 19:51 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 67f0943b394d 3c3cdf19 .config console log report C ci2-upstream-fs WARNING in nilfs_rmdir
2026/09/24 21:32 upstream f49a343b305c 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in nilfs_rmdir
* Struck through repros no longer work on HEAD.