[syzbot] [hardening?] [mm?] BUG: bad usercopy in con_font_op

[syzbot]

syzbot has bisected this issue to:

commit 24d69384bcd34b9dcaf5dab744bf7096e84d1abd
Author: Samuel Thibault <samuel.thibault at ens-lyon.org>
Date:   Thu Jan 19 15:19:16 2023 +0000

    VT: Add KD_FONT_OP_SET/GET_TALL operations

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=120b3232c80000
start commit:   2eb29d59ddf0 Merge tag 'drm-next-2023-03-03-1' of git://an..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=110b3232c80000
console output: https://syzkaller.appspot.com/x/log.txt?x=160b3232c80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cab35c936731a347
dashboard link: https://syzkaller.appspot.com/bug?extid=3af17071816b61e807ed
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10b71504c80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16f02d9cc80000

Reported-by: syzbot+3af17071816b61e807ed at syzkaller.appspotmail.com
Fixes: 24d69384bcd3 ("VT: Add KD_FONT_OP_SET/GET_TALL operations")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection