Re: KASAN: slab-out-of-bounds Write in vgacon_scroll

From: Sergey Senozhatsky
Date: Wed Jan 29 2020 - 09:18:05 EST


On (20/01/29 23:15), Sergey Senozhatsky wrote:
> Date: Wed, 29 Jan 2020 23:15:17 +0900
> From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> To: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>, anon anon <742991625abc@xxxxxxxxx>,
> wangkefeng.wang@xxxxxxxxxx, sergey.senozhatsky@xxxxxxxxx,
> syzkaller@xxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
> dri-devel@xxxxxxxxxxxxxxxxxxxxx, linux-fbdev@xxxxxxxxxxxxxxx
> Subject: Re: KASAN: slab-out-of-bounds Write in vgacon_scroll
> Message-ID: <20200129141517.GA13721@xxxxxxxxxxxxxxxxxxxxxxxx>
>
> On (20/01/28 15:58), Bartlomiej Zolnierkiewicz wrote:
> [..]
> >
> > Help is welcomed as I'm not going to look at it in the foreseeable future
> > (I'm busy enough with other things).
> >
> > > (dri-devel@xxxxxxxxxxxxxxxxxxxxx or linux-fbdev@xxxxxxxxxxxxxxx) into CC?
> >
> > Added to Cc:, thanks.
>
> Hmm. There is something strange about it. I use vga console quite
> often, and scrolling happens all the time, yet I can't get the same
> out-of-bounds report (nor have I ever seen it in the past), even with
> the reproducer. Is it supposed to be executed as it is, or are there
> any preconditions? Any chance that something that runs prior to that
> reproducer somehow impacts the system? Just asking.

These questions were addressed to anon anon (742991625abc@xxxxxxxxx),
not to Bartlomiej.

-ss