------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1601:11
index 27 is out of range for type 'struct lv[20]'
CPU: 1 UID: 0 PID: 15573 Comm: syz.5.1170 Tainted: G        W           syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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
 dtSplitPage+0x38d2/0x3b20 fs/jfs/jfs_dtree.c:1601
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x109b/0x5f40 fs/jfs/jfs_dtree.c:871
 jfs_create+0x6c8/0xa80 fs/jfs/namei.c:137
 vfs_create+0x24e/0x400 fs/namei.c:3405
 do_mknodat+0x3c6/0x4d0 fs/namei.c:4285
 __do_sys_mknod fs/namei.c:4318 [inline]
 __se_sys_mknod fs/namei.c:4316 [inline]
 __x64_sys_mknod+0x8c/0xa0 fs/namei.c:4316
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2f83e2ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2f8208e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007f2f84055fa0 RCX: 00007f2f83e2ebe9
RDX: 000000000000070b RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007f2f83eb1e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2f84056038 R14: 00007f2f84055fa0 R15: 00007ffd32b5afe8
 </TASK>
---[ end trace ]---