linux-kernel - Re: [RFC PATCH v4 00/13] module: core code clean up

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Message-ID: <1ae3a950-8c1e-a212-e557-8f112a16457d@csgroup.eu>
Date:   Thu, 3 Feb 2022 18:01:21 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Luis Chamberlain <mcgrof@...nel.org>,
        Aaron Tomlin <atomlin@...hat.com>,
        Michal Suchanek <msuchanek@...e.de>
CC:     "cl@...ux.com" <cl@...ux.com>,
        "pmladek@...e.com" <pmladek@...e.com>,
        "mbenes@...e.cz" <mbenes@...e.cz>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "jeyu@...nel.org" <jeyu@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-modules@...r.kernel.org" <linux-modules@...r.kernel.org>,
        "live-patching@...r.kernel.org" <live-patching@...r.kernel.org>,
        "atomlin@...mlin.com" <atomlin@...mlin.com>,
        "ghalat@...hat.com" <ghalat@...hat.com>,
        "allen.lkml@...il.com" <allen.lkml@...il.com>,
        "void@...ifault.com" <void@...ifault.com>,
        "joe@...ches.com" <joe@...ches.com>
Subject: Re: [RFC PATCH v4 00/13] module: core code clean up

Le 03/02/2022 à 01:20, Luis Chamberlain a écrit :
> On Sun, Jan 30, 2022 at 09:32:01PM +0000, Aaron Tomlin wrote:
>> Hi Luis,
>>
>> As per your suggestion [1], this is an attempt to refactor and split
>> optional code out of core module support code into separate components.
>> This version is based on branch mcgrof/modules-next since a97ac8cb24a3/or
>> modules-5.17-rc1. Please let me know your thoughts.
>>
>> Changes since v1 [2]:
> 

I have another comment: I think patch 5 should be dropped.

Having something behave based on a CONFIG_ARCH_HAS_SOMETHING item is 
wrong. It is not because a plateform selects 
CONFIG_ARCH_HAS_STRICT_MODULE_RWX that the module core should behave 
differentely than with other platforms as far as the user has not 
selected CONFIG_STRICT_MODULE_RWX.

And the topic here is wrong. It is a coincidence if making that stuff 
depend on CONFIG_ARCH_HAS_STRICT_MODULE_RWX works. This is just because 
the only architectures that do the module allocation without Exec flag 
are architectures that have also selected 
CONFIG_ARCH_HAS_STRICT_MODULE_RWX. But it should also work on other 
architectures.

I don't know exactly what was the motivation for commit 93651f80dcb6 
("modules: fix compile error if don't have strict module rwx") at the 
first place but it is just wrong and we should fix it.

module_enable_x() should work just fine regardless of 
CONFIG_ARCH_HAS_STRICT_MODULE_RWX.

Thanks
Christophe