------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3700:8
index -1 is out of range for type 'struct dtslot[128]'
CPU: 0 UID: 0 PID: 11002 Comm: syz.5.606 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 ubsan_epilogue+0xa/0x30
 __ubsan_handle_out_of_bounds+0xe8/0xf0
 dtInsertEntry+0x936/0x1430
 dtSplitPage+0x290b/0x37c0
 dtInsert+0x10a4/0x5f10
 jfs_mkdir+0x783/0xb00
 vfs_mkdir+0x413/0x630
 filename_mkdirat+0x285/0x510
 __se_sys_mkdirat+0x35/0x150
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f19ddb9b607
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:00007f19deacde58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f19deacdee0 RCX: 00007f19ddb9b607
RDX: 00000000000001ff RSI: 00002000000000c0 RDI: 00000000ffffff9c
RBP: 0000200000000080 R08: 0000200000000140 R09: 0000000000000000
R10: 0000200000000080 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007f19deacdea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
---[ end trace ]---
