linux-kernel - Re: [PATCH v4] x86: Disable image size check for test builds

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Message-ID: <e408cae6-0c40-44e6-b66e-53dbd6a2d854@intel.com>
Date: Thu, 17 Apr 2025 06:38:12 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Guenter Roeck <linux@...ck-us.net>, x86@...nel.org
Cc: Andrey Ryabinin <ryabinin.a.a@...il.com>,
 Alexander Potapenko <glider@...gle.com>,
 Andrey Konovalov <andreyknvl@...il.com>, Dmitry Vyukov <dvyukov@...gle.com>,
 Vincenzo Frascino <vincenzo.frascino@....com>,
 Andrew Morton <akpm@...ux-foundation.org>, kasan-dev@...glegroups.com,
 linux-kernel@...r.kernel.org, "H . Peter Anvin" <hpa@...or.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH v4] x86: Disable image size check for test builds

On 4/17/25 05:36, Guenter Roeck wrote:
> Solve the build problem by disabling the image size check for test
> builds.

What _actually_ breaks when this assertion is in play? I assume upon
decompression that the kernel image overflows into the fixmap area and
then the fun begins.

Does anything useful come out of the kernel or is it just a fabulous crash?

Because COMPILE_TEST sounds pretty benign:

>           If you are a developer and want to build everything available, say Y
>           here. If you are a user/distributor, say N here to exclude useless
>           drivers to be distributed.

at the *LEAST* if we are going to go down this road, can we make the
help text more scary and tell users that they might end up with an
unbootable kernel?