UFO tlock:0xffffc900029aa1b0
------------[ 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: 5826 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
 dtSearch+0x1a66/0x21b0 fs/jfs/jfs_dtree.c:784
 jfs_lookup+0x1b0/0x420 fs/jfs/namei.c:1461
 __lookup_slow+0x2b7/0x410 fs/namei.c:1866
 lookup_slow+0x53/0x70 fs/namei.c:1883
 walk_component fs/namei.c:2229 [inline]
 lookup_last fs/namei.c:2730 [inline]
 path_lookupat+0x3f5/0x8c0 fs/namei.c:2754
 filename_lookup+0x256/0x5d0 fs/namei.c:2783
 user_path_at+0x3a/0x60 fs/namei.c:3576
 ksys_umount fs/namespace.c:2058 [inline]
 __do_sys_umount fs/namespace.c:2066 [inline]
 __se_sys_umount fs/namespace.c:2064 [inline]
 __x64_sys_umount+0xf6/0x170 fs/namespace.c:2064
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7711d9c117
Code: a2 c7 05 7c c4 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 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 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeefeb8d48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7711d9c117
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeefeb8e00
RBP: 00007ffeefeb8e00 R08: 00007ffeefeb9e00 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeefeb9ef0
R13: 00007f7711e0471f R14: 000000000002358c R15: 00007ffeefebafc0
 </TASK>
---[ end trace ]---