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From:   Ajay Kaher <akaher@vmware.com>
To:     <gregkh@linuxfoundation.org>
CC:     <b.zolnierkie@samsung.com>, <daniel.vetter@ffwll.ch>,
        <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
        <torvalds@linux-foundation.org>, <w@1wt.eu>,
        <yuanmingbuaa@gmail.com>, <srivatsab@vmware.com>,
        <srivatsa@csail.mit.edu>
Subject: [PATCH 4.4 20/46] fbcon: remove soft scrollback code
Date:   Mon, 28 Sep 2020 11:36:57 +0530
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> @@ -3378,7 +3054,6 @@ static const struct consw fb_con = {
>  	.con_font_default	= fbcon_set_def_font,
>  	.con_font_copy 		= fbcon_copy_font,
>  	.con_set_palette 	= fbcon_set_palette,
> -	.con_scrolldelta 	= fbcon_scrolldelta,
>  	.con_set_origin 	= fbcon_set_origin,
>  	.con_invert_region 	= fbcon_invert_region,
>  	.con_screen_pos 	= fbcon_screen_pos,

If I am not wrong, this change creates crash in v4.4.y.
As before calling con_scrolldelta, NULL check is missing inside
console_callback() for v4.4.y, refer:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/tty/vt/vt.c?h=linux-4.4.y#n2487

This NULL check was added in commit 97293de977365fe672daec2523e66ef457104921,
and this is not merged to v4.4.y

-Ajay