[moderation] [fs?] WARNING in __start_renaming

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 44696aa3a489 Merge tag 'input-for-v7.2-rc2' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1633d432580000
kernel config: https://syzkaller.appspot.com/x/.config?x=98da55a882774dfe
dashboard link: https://syzkaller.appspot.com/bug?extid=3918032902853603c190
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/275821702e2a/disk-44696aa3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/29639898a8cd/vmlinux-44696aa3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/852434fd0e9e/bzImage-44696aa3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+391803...@syzkaller.appspotmail.com

------------[ 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


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