linux-kernel - Re: [RFC 12/12] module: use aliases to find module on find_module

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Message-ID: <18363c7d-ddec-df1a-8a8e-dd5321499545@suse.com>
Date:   Wed, 15 Mar 2023 15:43:54 +0100
From:   Petr Pavlu <petr.pavlu@...e.com>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org,
        christophe.leroy@...roup.eu, song@...nel.org,
        torvalds@...ux-foundation.org, pmladek@...e.com, david@...hat.com,
        prarit@...hat.com
Subject: Re: [RFC 12/12] module: use aliases to find module on
 find_module_all()

On 3/11/23 06:17, Luis Chamberlain wrote:
> Modules can have a series of aliases, but we don't currently use
> them to check if a module is already loaded. Part of this is because
> load_module() will stick to checking for already loaded modules using
> the actual module name, not an alias. Its however desriable to also
> check for aliases on find_module_all() for existing callers and future
> callers. The curent gain to using aliases on find_module_all() will
> simply be to be able to support unloading modules using the alias using
> the delete_module() syscall.

Different modules can have same aliases. Running
'sort modules.alias | cut -d' ' -f2 | uniq -dc' shows a list of them.
When a modprobe load of such an alias is requested, my reading is that this
new find_module_all() logic (if enabled) causes that only the first matched
module is inserted and others get recognized as duplicates, which doesn't look
right to me.

In general, I'm not sure that I understand motivation to keep track of these
aliases in the kernel. Do you have links to previous discussions that I could
perhaps read?

Thanks,
Petr