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Subject: Re: [PATCH] Raise the minimum GCC version to 5.2
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        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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From:   Christophe Leroy <christophe.leroy@csgroup.eu>
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Date:   Tue, 4 May 2021 14:26:18 +0200
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Le 04/05/2021 à 14:17, Michal Suchánek a écrit :
> On Tue, May 04, 2021 at 02:09:24PM +0200, Miguel Ojeda wrote:
>> On Tue, May 4, 2021 at 11:22 AM Michal Suchánek <msuchanek@suse.de> wrote:
>>>
>>> Except it makes answering the question "Is this bug we see on this
>>> ancient system still present in upstream?" needlessly more difficult to
>>> answer.
>>
>> Can you please provide some details? If you are talking about testing
>> a new kernel image in the ancient system "as-is", why wouldn't you
>> build it in a newer system? If you are talking about  particular
>> problems about bisecting (kernel, compiler) pairs etc., details would
>> also be welcome.
> 
> Yes, bisecting comes to mind. If you need to switch the userspace as
> well the bisection results are not that solid. You may not be even able
> to bisect because the workload does not exist on a new system at all.
> Crafting a minimal test case that can be forward-ported to a new system
> is not always trivial - if you understood the problem to that extent you
> might not even need to bisect it in the first place.
> 

But you don't need to switch the userspace or the complete build tools to build a kernel with a 
newer toolchain.

All you have to do is take one from https://mirrors.edge.kernel.org/pub/tools/crosstool/

I'm doing everything under CentOS 6, and using one of those tools allows me to build latest kernel 
without breaking anything else.