From mboxrd@z Thu Jan 1 00:00:00 1970 X-GM-THRID: 6647132102307348480 X-Received: by 2002:a19:f202:: with SMTP id q2mr751966lfh.8.1547666177589; Wed, 16 Jan 2019 11:16:17 -0800 (PST) X-BeenThere: isar-users@googlegroups.com Received: by 2002:a2e:814b:: with SMTP id t11-v6ls903791ljg.6.gmail; Wed, 16 Jan 2019 11:16:16 -0800 (PST) X-Google-Smtp-Source: ALg8bN7JbDsGqhNZTSmqAxNt+mfpyFNMBpUgXWGApPNHAJ3rTTfLnozDrkwqyuntIx1BeCA2GXuC X-Received: by 2002:a2e:482:: with SMTP id a2-v6mr738326ljf.28.1547666176897; Wed, 16 Jan 2019 11:16:16 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547666176; cv=none; d=google.com; s=arc-20160816; b=wqJp71ohCvmmqfyzmn9mJe2sVDFp/2AtrrUT0G4twlIT5NraZpof3yY0cQi6fkYqco TDTl57hsU9E1CBBBUizAt1G1ePQc1PhL01mrvYj96qv/4n5LCvW58OwNWJLQ9ap7nFN0 vfipTmmewUFk8fZhFfUM8HNTaqk35aJXP7sE7uhlYxKVdEBDBSmqPMUwjKhXHlv32uR4 d8F/QkK0w+BYIccCEDC23LDEMDfsM4fOZ0HF8rhgnDzZFco1URtUhuiMU3AZjJ6StWMn joe2o9vpdGRA0WVSbcm49EimhFwytwQ4q+Uh3SbgS7GbZ33ewCTNUvSZ4/ILchEpI/us AHRQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:to:subject; bh=zrYvl/4awCWN6G9IhxWltfOevVQdSBeV03eyOhRtah8=; b=Xa16JsXzwIFbhbrCiGxLmUt87/c2A1hgc25Kw8Wx933fYamn3W0LjZLf5AvUSIBMN9 2wp5kKgfG/IhD0POQT7J1KyrRoy74STCIGItlT23ay+mCUVyAKmLuc0wh/ThsZDDYwRa wMd+TGsH2JEYCgA7Tq8JCEni8whBOz7jnz5L4272v1WpQpSDKnofsVmiJX+p7rfrGCod ibGY1xw9/g1/0UXVeXfgl9YOxBXEVNBXOBnhhJqGnH3j+Mf7+ylWAJYLoo0tSv28Uax5 GDsuvlrWZEP+pmAq2ueW8owaffaib2pKtQ0UmxEM4AphmDFMl9bQmIxwt0kEH2dq0Ojp jk8A== ARC-Authentication-Results: i=1; gmr-mx.google.com; spf=pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.28 as permitted sender) smtp.mailfrom=jan.kiszka@siemens.com Return-Path: Received: from goliath.siemens.de (goliath.siemens.de. [192.35.17.28]) by gmr-mx.google.com with ESMTPS id 81-v6si264059ljc.2.2019.01.16.11.16.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Jan 2019 11:16:16 -0800 (PST) Received-SPF: pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.28 as permitted sender) client-ip=192.35.17.28; Authentication-Results: gmr-mx.google.com; spf=pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.28 as permitted sender) smtp.mailfrom=jan.kiszka@siemens.com Received: from mail1.sbs.de (mail1.sbs.de [192.129.41.35]) by goliath.siemens.de (8.15.2/8.15.2) with ESMTPS id x0GJGG7f020115 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 16 Jan 2019 20:16:16 +0100 Received: from [139.22.33.205] ([139.22.33.205]) by mail1.sbs.de (8.15.2/8.15.2) with ESMTP id x0GJGEWP032733; Wed, 16 Jan 2019 20:16:15 +0100 Subject: Re: custom-kernel downgrade and linux-libc-dev To: Henning Schild , isar-users References: <20190116172724.7811cfba@md1za8fc.ad001.siemens.net> From: Jan Kiszka Message-ID: Date: Wed, 16 Jan 2019 20:16:14 +0100 User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 In-Reply-To: <20190116172724.7811cfba@md1za8fc.ad001.siemens.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TUID: T89O5o5mdV/c On 16.01.19 17:27, Henning Schild wrote: > Hi, > > our custom kernel builds always generate a linux-libc-dev package > matching the kernel kernel version. So for a cip you would get > linux-libc-dev-4.4.xx. > > Prebuild debian packages from upstream depend on a linux-libc-dev >= > . I.e. you want build-essential in stretch, > you will end up with a "Depends: linux-libc-dev (>= 4.9.65-3)" > somewhere in your deps chain. > But if you are building a custom kernel lower than the expected version > you will end up with a smaller linux-libc-dev in the isar repo. And the > strong pinning will leave apt no choice but to give up and trying to > resolve the problem. So if you want to include i.e build-essential into > an image with a kernel downgrade, you will not be able to build that > image. > > That issue is especially problematic since it will creap into the > buildchroot after the package was deployed by the first kernel build. > And you will end up with a setup where partial rebuilds involving > buildchroot changes will not work anymore. > > In the layer i discovered this problem in i now remove the > linux-libc-dev package in a do_deploy_deb_prepend. That seems to be a > working hack for the downgrade case, but might not be the best idea for > an upgrade case. > > But my current suggestion would be to ignore the whole issue of kernel > header compatibilty and never deploy the linux-libc-dev package from > custom kernel builds. Thoughts? Better solution is to only deploy linux-libc-dev if it is newer than the distro version. If you do not do that, you would break applications that explicitly want to exploit interfaces of newer kernels. Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux