------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3697:15
index -1 is out of range for type 'dtslot [128]'
CPU: 0 UID: 0 PID: 22498 Comm: syz.4.4319 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455
 dtInsertEntry.isra.0+0x130f/0x1630 fs/jfs/jfs_dtree.c:3697
 dtSplitPage+0x231a/0x3660 fs/jfs/jfs_dtree.c:1593
 dtSplitUp+0x7b8/0x56a0 fs/jfs/jfs_dtree.c:1089
 dtInsert+0x8dd/0xb40 fs/jfs/jfs_dtree.c:868
 jfs_mkdir+0x641/0xb50 fs/jfs/namei.c:271
 vfs_mkdir+0x361/0x850 fs/namei.c:5261
 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5294
 __do_sys_mkdirat fs/namei.c:5315 [inline]
 __se_sys_mkdirat fs/namei.c:5312 [inline]
 __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5312
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff26a79b687
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007ff26b607e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ff26b607ee0 RCX: 00007ff26a79b687
RDX: 00000000000001ff RSI: 00002000000003c0 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000200000000140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000003c0
R13: 00007ff26b607ea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
---[ end trace ]---