syzbot


WARNING in __start_renaming

Status: moderation: reported on 2026/07/16 14:17
Subsystems: fs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+3918032902853603c190@syzkaller.appspotmail.com
First crash: 5d10h, last: 5d10h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
bb5f014f-1442-4cab-a34e-06a49a203ccc assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in __start_renaming 2026/07/14 00:01 2026/07/14 00:01 2026/07/14 00:58 2130f682322a1c2ef698e3c27a2b97e89e96142f

			
		

Sample crash report:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
WARNING: kernel/locking/rtmutex_common.h:193 at debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline], CPU#1: syz.4.105/6379
WARNING: kernel/locking/rtmutex_common.h:193 at rt_mutex_slowunlock+0x732/0xa20 kernel/locking/rtmutex.c:1432, CPU#1: syz.4.105/6379
Modules linked in:
CPU: 1 UID: 0 PID: 6379 Comm: syz.4.105 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline]
RIP: 0010:rt_mutex_slowunlock+0x739/0xa20 kernel/locking/rtmutex.c:1432
Code: af 8f 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 cf 02 00 00 83 3d db f7 6b 04 00 75 13 48 8d 3d 3e 3c 6f 04 48 c7 c6 a0 ff 6c 8b <67> 48 0f b9 3a 90 e9 d1 f9 ff ff 48 8d 3d 35 3c 6f 04 67 48 0f b9
RSP: 0000:ffffc90007acfba0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff888060a96df0 RCX: 0000000000080000
RDX: ffffc9001167e000 RSI: ffffffff8b6cffa0 RDI: ffffffff8fb2d7b0
RBP: ffffc90007acfc98 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f5f269 R12: dffffc0000000000
R13: 1ffff92000f59f7c R14: ffff888060a96da0 R15: 0000000000000246
FS:  00007f95146146c0(0000) GS:ffff888125d49000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f95141f0ff8 CR3: 000000003a202000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1034 [inline]
 unlock_rename fs/namei.c:3836 [inline]
 __start_renaming+0x34d/0x410 fs/namei.c:3919
 filename_renameat2+0x3a0/0x9b0 fs/namei.c:6167
 __do_sys_renameat2 fs/namei.c:6221 [inline]
 __se_sys_renameat2+0x5a/0x2c0 fs/namei.c:6216
 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: 0033:0x7f95163fde59
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:00007f9514614028 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007f9516686180 RCX: 00007f95163fde59
RDX: ffffffffffffff9c RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f9516493e6f R08: 0000000000000002 R09: 0000000000000000
R10: 00002000000004c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9516686218 R14: 00007f9516686180 R15: 00007ffc678f67d8
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	48 c1 e8 03          	shr    $0x3,%rax
   4:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax
   9:	84 c0                	test   %al,%al
   b:	0f 85 cf 02 00 00    	jne    0x2e0
  11:	83 3d db f7 6b 04 00 	cmpl   $0x0,0x46bf7db(%rip)        # 0x46bf7f3
  18:	75 13                	jne    0x2d
  1a:	48 8d 3d 3e 3c 6f 04 	lea    0x46f3c3e(%rip),%rdi        # 0x46f3c5f
  21:	48 c7 c6 a0 ff 6c 8b 	mov    $0xffffffff8b6cffa0,%rsi
* 28:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2d:	90                   	nop
  2e:	e9 d1 f9 ff ff       	jmp    0xfffffa04
  33:	48 8d 3d 35 3c 6f 04 	lea    0x46f3c35(%rip),%rdi        # 0x46f3c6f
  3a:	67                   	addr32
  3b:	48                   	rex.W
  3c:	0f                   	.byte 0xf
  3d:	b9                   	.byte 0xb9

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/12 14:08 upstream 44696aa3a489 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in __start_renaming
* Struck through repros no longer work on HEAD.