linux-kernel - Re:Re: [PATCH] arm64/module: Support for patching modules during runtime

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Message-ID: <56b98f57.954f.1989890838d.Coremail.fanqincui@163.com>
Date: Mon, 11 Aug 2025 17:57:44 +0800 (CST)
From: fanqincui  <fanqincui@....com>
To: "Marc Zyngier" <maz@...nel.org>
Cc: "Will Deacon" <will@...nel.org>, catalin.marinas@....com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	"Fanqin Cui" <cuifq1@...natelecom.cn>, hanht2@...natelecom.cn
Subject: Re:Re: [PATCH] arm64/module: Support for patching modules during
 runtime



>Well, you can't know about that. We patch basic primitives such as
>atomics, system register access, and plenty of other things. These
>things need to interoperate with the rest of the kernel.
>
>It's already difficult to guarantee inside the kernel itself. Having
>it in random modules will be even harder.
>


Okay, so the kernel patches you mentioned, are they already patched
when the module is installed? This doesn't conflict with the kernel patching.
I mean, the specific patching within the module is up to me. If the
chicken-and-egg problem you mentioned exist, module developers
should avoid it in their own code. 


I think the kernel should provide modules with the ability to patch
themselves, right?


Fanqin





At 2025-08-11 16:55:55, "Marc Zyngier" <maz@...nel.org> wrote:
>On Mon, 11 Aug 2025 09:32:19 +0100,
>fanqincui <fanqincui@....com> wrote:
>> 
>> 
>> Hi marc,
>> The callback function is designed by the developer. Developers need
>> to use the callback function to patch their own module code. Under
>> this premise, developers are responsible for providing the correct
>> callback function.
>> A correct callback function implementation does not require further
>> patching.
>
>Well, you can't know about that. We patch basic primitives such as
>atomics, system register access, and plenty of other things. These
>things need to interoperate with the rest of the kernel.
>
>It's already difficult to guarantee inside the kernel itself. Having
>it in random modules will be even harder.
>
>> Furthermore, the callback itself must be executable. If the callback
>> function has problems, the module's functionality will be affected.
>
>Exactly. Hence my question.
>
>	M.
>
>-- 
>Without deviation from the norm, progress is not possible.