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 40CBB279794 for ; Wed, 28 Jan 2026 14:22:08 +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=1769610129; cv=none; b=smmzYAMkHCwoKX/qiGjNi17SLeibUwONuAjj2U74jTi0h0h5/w+9NvCT+aGj+yoLCU1OpAlEwYByRMRzcO0NY6SEpG4v+csWcuUBDp3iZnApYwVURg9T9dgMrZ7+jMJvL2ImORQFRjCjr83YeUOb6KaJ4Jsz3fUHTHnLz8/FLA0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769610129; c=relaxed/simple; bh=FR/Fvb1i/90GdizSuMykaQQ0KQmFhPGbd+Ge4zPt5vo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aGdCz7ohI9SxQavGq1siur3x+bkvLaUaNB5hBeIubGRSQ8PZ9kpX0Jgrx7Myrl+PzZB8yNE4ly8dwNJsjLga7EDop8bpkVrPrucVTkf2BLtA3auznJo/X7CZ1ly2WolU9Vn4cIRcj7dpmXZajdoEMcMZf8hmMkzxzughVxv2jAE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gRKXGVnz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gRKXGVnz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F1B1C4CEF1; Wed, 28 Jan 2026 14:22:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769610128; bh=FR/Fvb1i/90GdizSuMykaQQ0KQmFhPGbd+Ge4zPt5vo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gRKXGVnzDw/OVYZoRFM7momACzw3EI8XaFQ3WNepVehtsxCoxQFq2BT33Ja/UJCi4 Yav1dck3+C5leWtUeSxKccJujVLTAB7M6uwCeXZ2n8P2TmNGJEdHRCAttC5Bwy0C6D Rf1oBob1Gp+joc7bzGWdyo4DXnJjQmdQszJhczq8= Date: Wed, 28 Jan 2026 15:21:33 +0100 From: Greg Kroah-Hartman To: "Barry K. Nathan" Cc: Ben Hutchings , Sasha Levin , Thorsten Glaser , Helge Deller , Junjie Cao , Gianluca Renzi , =?iso-8859-1?Q?Camale=F3n?= , William Burrow , 1123750@bugs.debian.org, Salvatore Bonaccorso , stable Subject: Re: [5.10] regression: virtual consoles 2-12 unusable Message-ID: <2026012823-carry-velvet-c587@gregkh> References: <176626831842.2137.9290349746475307418.reportbug@x61p.mirbsd.org> <176626831842.2137.9290349746475307418.reportbug@x61p.mirbsd.org> <2026010803-gem-puzzle-640d@gregkh> <64874115-dcc0-4f3d-9a82-2ad2abf86fbb@pobox.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64874115-dcc0-4f3d-9a82-2ad2abf86fbb@pobox.com> On Thu, Jan 15, 2026 at 12:41:10AM -0800, Barry K. Nathan wrote: > On 1/8/26 5:23 AM, Greg Kroah-Hartman wrote: > > On Fri, Jan 02, 2026 at 05:26:22PM +0100, Ben Hutchings wrote: > > > Hello stable maintainers, > > > > > > Several Debian users reported a regression after updating to kernel > > > version 5.10.247. > > > > > > Commit f0982400648a ("fbdev: Add bounds checking in bit_putcs to fix > > > vmalloc-out-of-bounds"), a backport of upstream commit 3637d34b35b2, > > > depends on vc_data::vc_font.charcount being initialised correctly. > > > > > > However, before commit a1ac250a82a5 ("fbcon: Avoid using FNTCHARCNT() > > > and hard-coded built-in font charcount") in 5.11, this member was set > > > to 256 for VTs initially created with a built-in font and 0 for VTs > > > initially created with a user font. > > > > > > Since Debian normally sets a user font before creating VTs 2 and up, > > > those additional VTs became unusable. VT 1 also doesn't work correctly > > > if the user font has > 256 characters, and the bounds check is > > > ineffective if it has < 256 characters. > > > > > > This can be fixed by backporting the following commits from 5.11: > > > > > > 7a089ec7d77f console: Delete unused con_font_copy() callback implementations > > > 259a252c1f4e console: Delete dummy con_font_set() and con_font_default() callback implementations > > > 4ee573086bd8 Fonts: Add charcount field to font_desc > > > 4497364e5f61 parisc/sticore: Avoid hard-coding built-in font charcount > > > a1ac250a82a5 fbcon: Avoid using FNTCHARCNT() and hard-coded built-in font charcount > > > > > > These all apply without fuzz and builds cleanly for x86_64 and parisc64. > > > > > > I tested on x86_64 that: > > > > > > - VT 2 works again > > > - bit_putcs_aligned() is setting charcnt = 256 > > > - After loading a font with 512 characters, bit_putcs_aligned() sets > > > charcnt = 512 and is able to display characters at positions >= 256 > > > > All now queued up, thanks! > > > > greg k-h > > For what it's worth, now that the above commits are queued up for 5.10.y: > There are two more commits, which were previously applied to 5.15.y, that > now apply to 5.10.y without merge conflicts (also without fuzz, if you apply > the 5.15.y versions of the patches): > > > a5a923038d70 > fbdev: fbcon: Properly revert changes when vc_resize() failed > (previously applied to 5.15.64 and 5.19.6) > > 3c3bfb8586f8 > fbdev: fbcon: release buffer when fbcon_do_set_font() failed > (previously applied to 5.15.86, 6.0.16, and 6.1.2) > > > After looking at these two commits, it seems to me that they are now > applicable to 5.10.y, and I think they probably should be applied (unless > I'm overlooking or missing something). Both now applied, thanks! greg k-h