[syzbot] [reiserfs?] UBSAN: array-index-out-of-bounds in direntry_create_vi

Hello,

syzbot found the following issue on:

HEAD commit:    1f6ce8392d6f Add linux-next specific files for 20230613
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=164a5a9b280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d103d5f9125e9fe9
dashboard link: https://syzkaller.appspot.com/bug?extid=e5bb9eb00a5a5ed2a9a2
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2d9bf45aeae9/disk-1f6ce839.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e0b03ef83e17/vmlinux-1f6ce839.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b6c21a24174d/bzImage-1f6ce839.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

REISERFS (device loop2): checking transaction log (loop2)
REISERFS (device loop2): Using r5 hash to sort names
reiserfs: enabling write barrier flush mode
REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
================================================================================
UBSAN: array-index-out-of-bounds in fs/reiserfs/item_ops.c:485:21
index 1 is out of range for type '__u16 [1]'
CPU: 1 PID: 10154 Comm: syz-executor.2 Not tainted 6.4.0-rc6-next-20230613-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_out_of_bounds+0xd5/0x140 lib/ubsan.c:348
 direntry_create_vi+0x8db/0x9f0 fs/reiserfs/item_ops.c:485
 create_virtual_node+0x748/0x1a70 fs/reiserfs/fix_node.c:115
 ip_check_balance fs/reiserfs/fix_node.c:1412 [inline]
 check_balance fs/reiserfs/fix_node.c:2083 [inline]
 fix_nodes+0x42e9/0x8660 fs/reiserfs/fix_node.c:2635
 reiserfs_paste_into_item+0x51a/0x8d0 fs/reiserfs/stree.c:2128
 reiserfs_get_block+0x165c/0x4100 fs/reiserfs/inode.c:1069
 __block_write_begin_int+0x3b1/0x14a0 fs/buffer.c:2128
 reiserfs_write_begin+0x36e/0xa60 fs/reiserfs/inode.c:2773
 generic_cont_expand_simple+0x117/0x1f0 fs/buffer.c:2488
 reiserfs_setattr+0x395/0x1370 fs/reiserfs/inode.c:3304
 notify_change+0xb2c/0x1180 fs/attr.c:483
 do_truncate+0x143/0x200 fs/open.c:66
 do_sys_ftruncate+0x549/0x780 fs/open.c:194
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd1ea48c199
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd1eb140168 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007fd1ea5abf80 RCX: 00007fd1ea48c199
RDX: 0000000000000000 RSI: 0000000006000000 RDI: 0000000000000005
RBP: 00007fd1ea4e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe9b988ecf R14: 00007fd1eb140300 R15: 0000000000022000
 </TASK>
================================================================================


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