[syzbot] [jfs?] UBSAN: array-index-out-of-bounds in dtInsertEntry

[syzbot <syzbot+5f7f0caf9979e9d09ff8@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    e7ed34365879 Merge tag 'mailbox-v6.12' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164e8127980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=84a3f3ed29aaafa0
dashboard link: https://syzkaller.appspot.com/bug?extid=5f7f0caf9979e9d09ff8
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eb021424c7db/disk-e7ed3436.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2f5f0d22ea96/vmlinux-e7ed3436.xz
kernel image: https://storage.googleapis.com/syzbot-assets/47176809b11c/bzImage-e7ed3436.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f7f0caf9979e9d09ff8@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3632:9
index 27 is out of range for type 'struct lv[20]'
CPU: 1 UID: 0 PID: 5469 Comm: syz.1.37 Not tainted 6.11.0-syzkaller-12113-ge7ed34365879 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429
 dtInsertEntry+0x174e/0x1780 fs/jfs/jfs_dtree.c:3632
 dtSplitPage+0x2d99/0x3ed0 fs/jfs/jfs_dtree.c:1595
 dtSplitUp fs/jfs/jfs_dtree.c:1091 [inline]
 dtInsert+0x14bd/0x6c10 fs/jfs/jfs_dtree.c:870
 jfs_create+0x7ba/0xbb0 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3595 [inline]
 open_last_lookups fs/namei.c:3694 [inline]
 path_openat+0x1c03/0x3590 fs/namei.c:3930
 do_filp_open+0x235/0x490 fs/namei.c:3960
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_creat fs/open.c:1506 [inline]
 __se_sys_creat fs/open.c:1500 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1500
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2c1f97dff9
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:00007f2c20746038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f2c1fb35f80 RCX: 00007f2c1f97dff9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000e00
RBP: 00007f2c1f9f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2c1fb35f80 R15: 00007ffdc44cf8d8
 </TASK>
---[ end trace ]---


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup