Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27ECFC433F5 for ; Sat, 25 Dec 2021 01:08:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232045AbhLYBIP (ORCPT ); Fri, 24 Dec 2021 20:08:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229549AbhLYBIP (ORCPT ); Fri, 24 Dec 2021 20:08:15 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B05A7C061401; Fri, 24 Dec 2021 17:08:14 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id f18-20020a17090aa79200b001ad9cb23022so9472620pjq.4; Fri, 24 Dec 2021 17:08:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EL3Dq5TmzKZTYH6R2nxXnIMQFNr3bo4ypkh6vrYhshc=; b=ANTs6AaMh9Xv+SEq9FN84UnQyFkAK1wzteyLgRzWsZm/ZIXEny+gVkpCCF38PmCCPD U3kVZ17ysox/ZyS+K2kYpIuRBKB7eTCl3r04NqQ/013gVFmp5eQUcU0890833IUYF9kZ wiVgM5kJsRssyTvs/JvHwiyYbncWnH2EKHVp9uw97vjCm+AaIb2VUlzDR998e0qfYHwH 44Tq0lIMr9S0xcf78NXAlzvWPCTBG9HJCkrflYqYbyrMsJ6vrp68nc4WHSGMjVAbW/vj XE2FQZrk7zzAiTZplGbydnc7CNJuAGcUVU/sHqsv5QQyCREB1oOk5eGr016PuYKzIiCQ mLTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=EL3Dq5TmzKZTYH6R2nxXnIMQFNr3bo4ypkh6vrYhshc=; b=ShZBsrZPEyapMIPQNsq4mYVLCMqek/MvIft9DShmyqgT+h/ZQ+Xb6OtktI5eN0ukhN L5T6UZEndJ98j6uukZJlwXx8ZJUiYGzvphYaw/YDWHZYKC0TC75k+2cmRaM2KyTOFrbj G5MkrHyXH4y7RJSwteo/z2TpPa2iQg0bb3AEVgUSe5wdHrNUGAyij4MlUbaBddpGblQo B3um8gxAHP5FgMYgVkt5VBIz8GIpHr485AjCbkv5PNQq9xfUXUwLBXch0Lao/RxoRpOC ysbWzABn9RjWxi5NC329nswB9lMJyZrTWKcV22evzvnmp0jsMGPqYra/G0rQzilVsI+c lJkg== X-Gm-Message-State: AOAM532BV2tQgokPIgq1NlfaRTqGPyN/PEijnZaN4Ry7H9GE1aDe+qYI vQn/IH0QBVCy/LkvQ/rQh7B5PNEKfbMjKr5SMVk= X-Google-Smtp-Source: ABdhPJzfK61jo474Cn7NsNqiEL1YxMVo77g1HDHOVNp8m8YOqeXaNFT2FKY6v56SdxDN1qkFoVjO/Q1A6KMul1lntKc= X-Received: by 2002:a17:903:1212:b0:148:ac36:25fb with SMTP id l18-20020a170903121200b00148ac3625fbmr8470206plh.147.1640394493261; Fri, 24 Dec 2021 17:08:13 -0800 (PST) MIME-Version: 1.0 References: <20211222132332.7817-1-vimal.agrawal@sophos.com> In-Reply-To: From: Vimal Agrawal Date: Sat, 25 Dec 2021 06:38:02 +0530 Message-ID: Subject: Re: [PATCH v2] kernel/module.c: heuristic enhancement when INSTALL_MOD_STRIP= "--strip-unneeded" is used To: Christoph Hellwig Cc: Luis Chamberlain , Vimal Agrawal , Masahiro Yamada , Michal Marek , Nick Desaulniers , Jan Beulich , Jeff Mahoney , Sam Ravnborg , linux-kbuild@vger.kernel.org, jeyu@kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 24, 2021 at 12:17 PM Christoph Hellwig wrote: > > I don't think we can support passing arbitrary linker options and > expects things to work. If we want to support --strip-unneeded > it needs a good rationale and be added as a direct config option. INSTALL_MOD_STRIP was provided to give flexibility for providing strippping options. It will be a separate discussion if we want to continue allowing this flexibility or not but it is available now. I see that it works but just that it is behaving erratically during symbol decodes. I tried few other stripping options. --strip-all does not work and insmod fails as it needs some symbols which is fine as it is hinting the user there is a problem with stripping option. This is not the case with --strip-unneeded option as it builds and loads/works fine but fails to decode symbols properly sometimes. One of the rationale for --strip-unneeded option is that it significantly reduces the size of .ko without affecting its functionality ( though debuggability takes a hit). I guess many platforms/products that need limited memory footprint might be using this option. I am fine if we decide to say that --strip-unneeded option is not supported by kbuild/INSTALL_MOD_STRIP which is not the case now. In that case, I agree that this patch will not even be required. Vimal