From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A917C433DB for ; Thu, 4 Feb 2021 08:51:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E969564E4B for ; Thu, 4 Feb 2021 08:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235153AbhBDIv4 (ORCPT ); Thu, 4 Feb 2021 03:51:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:46094 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234966AbhBDIvt (ORCPT ); Thu, 4 Feb 2021 03:51:49 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3424D64F4D; Thu, 4 Feb 2021 08:51:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612428666; bh=7uCkM47OIUuWPJjtJG/o3Oocyx2ATU2RpCB1ZqlaX4w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0TgoXiujRPg2i+I4COX+3BRNrCQytaX536kxCwDEYwC3iA3adXL0ts9Q/dqfUfIa8 gECBaG9uJNwmeHGrwUCpKsk70QL1H/SXfErR8fk+V0/sZzmBJBEOIMIwFlB8CljSLK 0Vh5qEYiCXyhhTq9iePZp4/xrPSaGu5bbg9iwQwc= Date: Thu, 4 Feb 2021 09:51:03 +0100 From: Greg Kroah-Hartman To: Jiri Slaby Cc: Jari Ruusu , Sasha Levin , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "torvalds@linux-foundation.org" , masahiroy@kernel.org Subject: Re: Kernel version numbers after 4.9.255 and 4.4.255 Message-ID: References: <7pR0YCctzN9phpuEChlL7_SS6auHOM80bZBcGBTZPuMkc6XjKw7HUXf9vZUPi-IaV2gTtsRVXgywQbja8xpzjGRDGWJsVYSGQN5sNuX1yaQ=@protonmail.com> <78ada91b-21ee-563f-9f75-3cbaeffafad4@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <78ada91b-21ee-563f-9f75-3cbaeffafad4@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 04, 2021 at 08:26:04AM +0100, Jiri Slaby wrote: > On 04. 02. 21, 7:20, Greg Kroah-Hartman wrote: > > On Thu, Feb 04, 2021 at 05:59:42AM +0000, Jari Ruusu wrote: > > > Greg, > > > I hope that your linux kernel release scripts are > > > implemented in a way that understands that PATCHLEVEL= and > > > SUBLEVEL= numbers in top-level linux Makefile are encoded > > > as 8-bit numbers for LINUX_VERSION_CODE and > > > KERNEL_VERSION() macros, and must stay in range 0...255. > > > These 8-bit limits are hardcoded in both kernel source and > > > userspace ABI. > > > > > > After 4.9.255 and 4.4.255, your scripts should be > > > incrementing a number in EXTRAVERSION= in top-level > > > linux Makefile. > > > > Should already be fixed in linux-next, right? > > I assume you mean: > commit 537896fabed11f8d9788886d1aacdb977213c7b3 > Author: Sasha Levin > Date: Mon Jan 18 14:54:53 2021 -0500 > > kbuild: give the SUBLEVEL more room in KERNEL_VERSION > > That would IMO break userspace as definition of kernel version has changed. > And that one is UAPI/ABI (see include/generated/uapi/linux/version.h) as > Jari writes. For example will glibc still work: > http://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/configure.ac;h=13abda0a51484c5951ffc6d718aa36b72f3a9429;hb=HEAD#l14 > > ? Or gcc 10 (11 will have this differently): > https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/bpf/bpf.c;hb=ee5c3db6c5b2c3332912fb4c9cfa2864569ebd9a#l165 > > and > > https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/bpf/bpf-helpers.h;hb=ee5c3db6c5b2c3332912fb4c9cfa2864569ebd9a#l53 Ugh, I thought this was an internal representation, not an external one :( > It might work somewhere, but there are a lot of (X * 65536 + Y * 256 + Z) > assumptions all around the world. So this doesn't look like a good idea. Ok, so what happens if we "wrap"? What will break with that? At first glance, I can't see anything as we keep the padding the same, and our build scripts seem to pick the number up from the Makefile and treat it like a string. It's only the crazy out-of-tree kernel stuff that wants to do minor version checks that might go boom. And frankly, I'm not all that concerned if they have problems :) So, let's leave it alone and just see what happens! greg k-h