From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD06F1E2858; Thu, 31 Jul 2025 07:22:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753946556; cv=none; b=eY839R+8LnZ4aj6DVJioju+/C+dHLWailzFfBIqqNhW/lFQ9PLLsJjI2WrsxnTEzP5jcJGI88ngo6V6RJhvaAlPq+IJ8Fsw/caYRg1KYtGZq6t7qixtfRfJyeFNaFTA+6Ar914W00bjO3ioTxq0zeb6GR4gbAOj8gi1h5ArgtKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753946556; c=relaxed/simple; bh=QkduE96G3GZOxPivBjY/bua13Jnmn6RTSM22/Y1k/Ow=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OEP9g4atMZnYFDigPfV1ajlie351v4HLLEE0Nokp4mfPm/4yg0RFq/jb/LE3zGOXl/wjTZRByDRFwl9vrbkq5k3PixWZDAPNWntwjQmSCbuZnVHM2Hx6dFlF/nsjTG/YPJmFEgxIeAulx42UIKZOXfW2yd3X1k4w70zr8A5NELI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PtxS8+ff; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PtxS8+ff" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D584C4CEEF; Thu, 31 Jul 2025 07:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753946555; bh=QkduE96G3GZOxPivBjY/bua13Jnmn6RTSM22/Y1k/Ow=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PtxS8+ffV+VNlFMcNtPKSs9llPSBjvPQoV2i3yFK4K/BJg5Yu6Rt7ZyzWWlR9Blal ohEXGzSxiYy/o9kAj2D4n5wpaBhSE6Vd9QCflGhSkccUZ60b8iLJDeWrnViBJm9OYK hjigdso+I27Tb8jRS90u6W5/mO3k0msClwuO2OVFM5ZD00p+10jBJoIg2oH1jEOwGk jbbeMQbaAxiYhSleYn4A0LOPkRaQ4GXbISoVIrpYzs8FrYeiSVpH9i3lsFlVzPBt/z 9ogTAe2zdqPbO8KsJxcl3MpBa471hjI2hMjHdlCp5xYF1EpukzrBNX5nZZXhuyADA/ lbY7mijFMxUOw== Message-ID: Date: Thu, 31 Jul 2025 09:22:31 +0200 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Text mode VGA-console scrolling is broken in upstream & stable trees To: Jari Ruusu , Yi Yang , GONG Ruiqi , Helge Deller , Greg Kroah-Hartman , Sasha Levin , Linus Torvalds Cc: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 30. 07. 25, 16:06, Jari Ruusu wrote: > The patch that broke text mode VGA-console scrolling is this one: > "vgacon: Add check for vc_origin address range in vgacon_scroll()" > commit 864f9963ec6b4b76d104d595ba28110b87158003 upstream. > > How to preproduce: > (1) boot a kernel that is configured to use text mode VGA-console > (2) type commands: ls -l /usr/bin | less -S > (3) scroll up/down with cursor-down/up keys > > Above mentioned patch seems to have landed in upstream and all > kernel.org stable trees with zero testing. Even minimal testing > would have shown that it breaks text mode VGA-console scrolling. At the time this was posted (privately and on security@), I commented: ===== > --- a/drivers/video/console/vgacon.c > +++ b/drivers/video/console/vgacon.c > @@ -1168,7 +1168,7 @@ static bool vgacon_scroll(struct vc_data *c, unsigned int t, unsigned int b, > c->vc_screenbuf_size - delta); > c->vc_origin = vga_vram_end - c->vc_screenbuf_size; > vga_rolled_over = 0; > - } else > + } else if (oldo - delta >= (unsigned long)c->vc_screenbuf) > c->vc_origin -= delta; IMO you should also add: else c->vc_origin = c->vc_screenbuf; Or clamp 'delta' beforehand and don't add the 'if'. ===== That did not happen, AFAICS. Care to test the above suggestion? thanks, -- js suse labs