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Sender: Guenter Roeck <groeck7@gmail.com>
Subject: Re: [PATCH] Enable '-Werror' by default for all kernel builds
To:     Christoph Hellwig <hch@infradead.org>,
        Marco Elver <elver@google.com>
Cc:     Nathan Chancellor <nathan@kernel.org>,
        Arnd Bergmann <arnd@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Albert Ou <aou@eecs.berkeley.edu>,
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        Alexander Potapenko <glider@google.com>,
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        Andrey Konovalov <andreyknvl@gmail.com>,
        kasan-dev@googlegroups.com,
        Christian =?unknown-8bit?B?S8O2bmln?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>, amd-gfx@lists.freedesktop.org
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From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <a04c4c37-7151-ef7e-09ce-a61ac7b12106@roeck-us.net>
Date:   Wed, 8 Sep 2021 23:07:55 -0700
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On 9/8/21 10:58 PM, Christoph Hellwig wrote:
> On Wed, Sep 08, 2021 at 11:58:56PM +0200, Marco Elver wrote:
>> It'd be good to avoid. It has helped uncover build issues with KASAN in
>> the past. Or at least make it dependent on the problematic architecture.
>> For example if arm is a problem, something like this:
> 
> I'm also seeing quite a few stack size warnings with KASAN on x86_64
> without COMPILT_TEST using gcc 10.2.1 from Debian.  In fact there are a
> few warnings without KASAN, but with KASAN there are a lot more.
> I'll try to find some time to dig into them.
> 
> While we're at it, with -Werror something like this is really futile:
> 
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c: In function ‘amdgpu_bo_support_uswc’:
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c:493:2: warning: #warning
> Please enable CONFIG_MTRR and CONFIG_X86_PAT for better performance thanks to write-combining [-Wcpp
>    493 | #warning Please enable CONFIG_MTRR and CONFIG_X86_PAT for better performance \
>        |  ^~~~~~~
> 

I have been wondering if all those #warning "errors" should either
be removed or be replaced with "#pragma message".

Guenter