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 F023118C322; Fri, 15 Nov 2024 09:22:16 +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=1731662537; cv=none; b=uAKQ/MsFFQTCta6pw6tP5k5w1+LY6lggTjdnu1pYvkHdW/f8SV5KW04KzyX2a+SAT74pL2KGtURyJh9YvRH4p0zRqjS/fQ6QQJPdY6oD8UF45aJxa/dEvW07HSVdxKn/dPShb9PLFODAiwRum2/TnNvBcgtLFZ2CLYnP7Ufv3zo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731662537; c=relaxed/simple; bh=XAw7hxVKcfQgolreomu8qnqVYITQSexMqnTW646pREI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mtX586YJdqIllf2zdoW8VmsuJiOKz9hByIPOshLXWHW18fHfWTyysZxyTBDSvj+Kou4df7Pwpe66jCBQ7VqwHdd+Kv+26nyplihZbdvuxvIFJYZKj/BfuMmMUuaMLIZqNgpA+urC09QE7GpMx8N9XVSMbsC0LTVukfjTX0rtHCU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lD63Z5tw; 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="lD63Z5tw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EFC8C4CECF; Fri, 15 Nov 2024 09:22:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731662536; bh=XAw7hxVKcfQgolreomu8qnqVYITQSexMqnTW646pREI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lD63Z5twBZpCEMI6JV5mGGiUWk2w0Gu5EFcHQrw6Il8SmUjG+AWpfNZSA7ByL7s3h JKeCQmvsnHbHf9A11y3C0zjA9AlOOnthq8MSfu4haBM+PCpaVvypfq0ptsBwBmfd5J ksGRcJMyPF2sLaYPCamopmeNrow0deH9aKRfdSv0= Date: Fri, 15 Nov 2024 10:22:13 +0100 From: Greg KH To: Francesco Dolcini Cc: Parth Pancholi , Masahiro Yamada , Nathan Chancellor , Nicolas Schier , Parth Pancholi , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Francesco Dolcini Subject: Re: [PATCH v2] kbuild: switch from lz4c to lz4 for compression Message-ID: <2024111541-antiquity-footpath-e221@gregkh> References: <20241114145645.563356-1-parth105105@gmail.com> <2024111442-yeast-flail-fcea@gregkh> <20241115083940.GA3971@francesco-nb> 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: <20241115083940.GA3971@francesco-nb> On Fri, Nov 15, 2024 at 09:39:40AM +0100, Francesco Dolcini wrote: > Hello Greg, > > On Thu, Nov 14, 2024 at 05:02:01PM +0100, Greg KH wrote: > > On Thu, Nov 14, 2024 at 03:56:44PM +0100, Parth Pancholi wrote: > > > From: Parth Pancholi > > > > > > Replace lz4c with lz4 for kernel image compression. > > > Although lz4 and lz4c are functionally similar, lz4c has been deprecated > > > upstream since 2018. Since as early as Ubuntu 16.04 and Fedora 25, lz4 > > > and lz4c have been packaged together, making it safe to update the > > > requirement from lz4c to lz4. > > > > > > Consequently, some distributions and build systems, such as OpenEmbedded, > > > have fully transitioned to using lz4. OpenEmbedded core adopted this > > > change in commit fe167e082cbd ("bitbake.conf: require lz4 instead of > > > lz4c"), causing compatibility issues when building the mainline kernel > > > in the latest OpenEmbedded environment, as seen in the errors below. > > > > > > This change also updates the LZ4 compression commands to make it backward > > > compatible by replacing stdin and stdout with the '-' option, due to some > > > unclear reason, the stdout keyword does not work for lz4 and '-' works for > > > both. In addition, this modifies the legacy '-c1' with '-9' which is also > > > compatible with both. This fixes the mainline kernel build failures with > > > the latest master OpenEmbedded builds associated with the mentioned > > > compatibility issues. > > > > > > LZ4 arch/arm/boot/compressed/piggy_data > > > /bin/sh: 1: lz4c: not found > > > ... > > > ... > > > ERROR: oe_runmake failed > > > > > > Cc: stable@vger.kernel.org > > > > What bug does this resolve that it needs to be backported to stable > > kernels? > > This is not solving any existing actual bug, and therefore there is no > fixes tag. > > The issue here is that the kernel build system is using lz4c, that is > deprecated since 2018, and now distributions are actively moving away from it. > > openSUSE Tumbleweed and OE already removed it, so you would not be able > to compile a stable kernel on such distribution when using lz4 unless we > backport such a patch. > > Everything should be properly documented in the commit message already. > > My understanding is that something like that would be a reason for > backporting to stable, if my understanding is not correct we'll remove > the cc:stable and send a v3. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for what meets stable kernel requirements. I don't think that this patch is that. thanks, greg k-h