------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1598:11
index 27 is out of range for type 'struct[  209.988557][ T7038] index 27 is out of range for type 'struct lv[20]'
CPU: 0 UID: 0 PID: 7038 Comm: syz.3.187 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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
 dtSplitPage+0x34d0/0x36a0 fs/jfs/jfs_dtree.c:1598
 dtSplitUp fs/jfs/jfs_dtree.c:1089 [inline]
 dtInsert+0x1081/0x5cd0 fs/jfs/jfs_dtree.c:868
 jfs_create+0x75b/0xb10 fs/jfs/namei.c:138
 vfs_create+0x2d3/0x470 fs/namei.c:4204
 filename_mknodat+0x3ec/0x670 fs/namei.c:5170
 __do_sys_mknod fs/namei.c:5207 [inline]
 __se_sys_mknod+0x3a/0x150 fs/namei.c:5204
 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: 0033:0x7fc6ff86ce59
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:00007fc6fdac6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007fc6ffae5fa0 RCX: 00007fc6ff86ce59
RDX: 0000000000000707 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007fc6ff902d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6ffae6038 R14: 00007fc6ffae5fa0 R15: 00007ffdf8f26788
 </TASK>
---[ end trace ]---