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Mon, 03 May 2021 09:26:13 +0000 Received: from mail-wm1-f41.google.com ([209.85.128.41]) by mrelayeu.kundenserver.de (mreue108 [213.165.67.113]) with ESMTPSA (Nemesis) id 1MVvGt-1m2UMl0DXp-00RtDF; Mon, 03 May 2021 11:26:06 +0200 Received: by mail-wm1-f41.google.com with SMTP id u5-20020a7bc0450000b02901480e40338bso3152620wmc.1; Mon, 03 May 2021 02:26:05 -0700 (PDT) X-Gm-Message-State: AOAM530BbjWCl/9wT5pUl+H7p54H5RnkSUhBZVgduGXwWJHu6xrL34PJ PPmVbTucfgWpmtehpU2Mxn9qq+1zJpHkQrjnx40= X-Google-Smtp-Source: ABdhPJyImR0lXDOWh/rFmKSSJQOuX4SzDcgMMWQ8OtmjXS6cOp8lf5wEACKwu1MdktyqNDYlMn4UdggeZ8LLn0fAS0M= X-Received: by 2002:a7b:c344:: with SMTP id l4mr30642981wmj.120.1620033965603; Mon, 03 May 2021 02:26:05 -0700 (PDT) MIME-Version: 1.0 References: <20210501151538.145449-1-masahiroy@kernel.org> <3943bc020f6227c8801907317fc113aa13ad4bad.camel@perches.com> <20210502183030.GF10366@gate.crashing.org> <81a926a3bdb70debe3ae2b13655ea8d249fb9991.camel@perches.com> <20210502203253.GH10366@gate.crashing.org> <20210502223007.GZ1847222@casper.infradead.org> In-Reply-To: From: Arnd Bergmann Date: Mon, 3 May 2021 11:25:21 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] Raise the minimum GCC version to 5.2 To: Matthew Wilcox , Linus Torvalds , Segher Boessenkool , Joe Perches , Miguel Ojeda , Masahiro Yamada , Albert Ou , Arnd Bergmann , Linux Kbuild mailing list , Greg Kroah-Hartman , Jonathan Corbet , Linux Doc Mailing List , linux-kernel , Palmer Dabbelt , Paul Walmsley , Catalin Marinas , Miguel Ojeda , Paul Mackerras , linux-riscv , linuxppc-dev , Will Deacon , Linux ARM X-Provags-ID: V03:K1:dfF0glRwgJZb8sIdPte6x8c+oPsO7va6VRFuZtiqpEPqHpLWebf ITPeCDQkSqE4fke3nne040PqSBzm1QvXi8zvaRB6B4UO0DplEN95snpw9yKOlzm+eqdKc0w ItdktX1oWH+domOXvJR39lfPpSw5l+X593fxnEyRPpi46yqL5rAN0DqUUHEHRGCyVTOQDS3 S7zsuuzzFGW6OlKlQJhfA== X-UI-Out-Filterresults: notjunk:1;V03:K0:djw/hfV7cuQ=:oPg44G3dbPza8RnxAIMF05 ewrz9peMKs1f/CV7sLXFKf/gFmb9zHwiJctto60+Y8UKi86u6/QlDjPai7inWFrhmKynST8Fr qwy66OGURqVTyVqAHAwPPxy2GRCNio2ruEspjN1MSerAKhcTN60lb2dsv+D9eI+YZxpn3HZXE YEMKTTuPSv6IV6wlXR4ifecMt8fptICPJJmsi2aQUt7AQiaBjf6fA9aywruLEBYJD8Fn6vF15 h/YrrqaHnyLbfCY8qgZnKoUtFRiR3/CJqYUS7pKw+hoH9lzXe7CgFt6GPKLnfZTzM2A/2Nz8j jPI+/IGcLkXdckxz3r6NlS2LheiHt32Hw+hRfwCOrYuH0JBilAqWjmvzZoNiVZzVa8VCDR0ip nm0kM5vxa99ctBcMxqBlx9NPLnTi3hul/7cxxVwlcTvg7gePOEf3QMAXTEWtDfkyRwWdei96x iWn/qdnvOzXL22JHPNQKsR4CezjkcU+vN7S0QUafXBI8iAkshlBgpduldBHOfuZs942cOcLT4 2zTSO6D9giwp4+Z/4JWoY8= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210503_022611_799366_C6D49BF1 X-CRM114-Status: GOOD ( 20.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, May 3, 2021 at 9:35 AM Alexander Dahl wrote: > > Desktops and servers are all nice, however I just want to make you > aware, there are embedded users forced to stick to older cross > toolchains for different reasons as well, e.g. in industrial > environment. :-) > > This is no show stopper for us, I just wanted to let you be aware. Can you be more specific about what scenarios you are thinking of, what the motivations are for using an old compiler with a new kernel on embedded systems, and what you think a realistic maximum time would be between compiler updates? One scenario that I've seen previously is where user space and kernel are built together as a source based distribution (OE, buildroot, openwrt, ...), and the compiler is picked to match the original sources of the user space because that is best tested, but the same compiler then gets used to build the kernel as well because that is the default in the build environment. There are two problems I see with this logic: - Running the latest kernel to avoid security problems is of course a good idea, but if one runs that with ten year old user space that is never updated, the system is likely to end up just as insecure. Not all bugs are in the kernel. - The same logic that applies to ancient user space staying with an ancient compiler (it's better tested in this combination) also applies to the kernel: running the latest kernel on an old compiler is something that few people test, and tends to run into more bugs than using the compiler that other developers used to test that kernel. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel