Date:   Sun, 19 Feb 2023 16:21:46 -0500
From:   Storm Dragon <stormdragon2976@gmail.com>
To:     linux-kernel@vger.kernel.org
Subject: Bug with /dev/vcs* devices
Message-ID: <Y/KS6vdql2pIsCiI@hotmail.com>
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Howdy,

This is my first time ever submitting a kernel bug, so I apologize if this =
is the wrong place. As per the instructions I found, I first filed a bug in=
 Arch Linux:

https://bugs.archlinux.org/task/77575

I will add the contents of the response here:

For the record, here are the 2 associated mailing list threads [1][2].
                                                                           =
                                                                           =
          =20
The reason why it affects both LTS and current linux is because it appears =
a security patch was applied to both trees to fix a UAF (use after free) bu=
g.
                                                                           =
                                                                           =
          =20
If that patch is problematic, you should report it upstream to the kernel f=
olks. Maybe even email the patch author directly. It's this patch [3]. Plea=
se let us
know what you find out.
                                                                           =
                                                                           =
          =20
[1] https://lists.archlinux.org/archives/list/arch-general%40lists.archlinu=
x.org/thread/EOSHIVGUZLNAD7BPHSUGOXFYSAFWDYH7/
[2] https://lists.archlinux.org/archives/list/arch-general%40lists.archlinu=
x.org/thread/S6R6UDUMX2LWL4HJ74MFNYOES45UBFLF/
[3] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit=
/drivers/tty/vt/vc_screen.c?h=3Dv5.15.94&id=3Dfc9e27f3ba083534b8bbf72ab0f5c=
810ffdc7d18

----------End Response ----------

Methods for reproducing the bug are included in the link to the bug above. =
But I will include one of them here as well. As root:

[root@mjollnir ~]# cat /dev/vcsa1
                                                                           =
                                                                           =
          =20
    cat: /dev/vcsa1: No such device or address

The contents is displayed very briefly before the No such device or address=
 error.

Thank you,
Storm

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