Re: [PATCH 4.4 20/46] fbcon: remove soft scrollback code

[Greg KH]

On Mon, Sep 28, 2020 at 11:36:57AM +0530, Ajay Kaher wrote:
> > @@ -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

Good catch, will go queue up that portion of that commit to 4.4.y now,
thanks!

greg k-h