UFO tlock:0xffffc9000353a090
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:784:21
index -1 is out of range for type 'struct dtslot[128]'
CPU: 0 UID: 0 PID: 5802 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455
 dtSearch+0x1a66/0x21b0 fs/jfs/jfs_dtree.c:784
 jfs_lookup+0x155/0x380 fs/jfs/namei.c:1461
 __lookup_slow+0x29d/0x3d0 fs/namei.c:1816
 lookup_slow+0x53/0x70 fs/namei.c:1833
 walk_component+0x2d2/0x400 fs/namei.c:2151
 lookup_last fs/namei.c:2652 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2676
 filename_lookup+0x212/0x570 fs/namei.c:2705
 user_path_at+0x3a/0x60 fs/namei.c:3215
 ksys_umount fs/namespace.c:2052 [inline]
 __do_sys_umount fs/namespace.c:2060 [inline]
 __se_sys_umount fs/namespace.c:2058 [inline]
 __x64_sys_umount+0xee/0x160 fs/namespace.c:2058
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f432d2b0a77
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe8bbc3b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f432d2b0a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe8bbc3bc0
RBP: 00007ffe8bbc3bc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe8bbc4cb0
R13: 00007f432d333d7d R14: 00000000000315dc R15: 00007ffe8bbc5d80
 </TASK>
---[ end trace ]---