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From: Luis Chamberlain <mcgrof@kernel.org>
To: Petr Pavlu <petr.pavlu@suse.com>
Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org,
	christophe.leroy@csgroup.eu, song@kernel.org,
	torvalds@linux-foundation.org, pmladek@suse.com,
	david@redhat.com, prarit@redhat.com
Subject: Re: [RFC 12/12] module: use aliases to find module on find_module_all()
Date: Wed, 15 Mar 2023 09:12:38 -0700	[thread overview]
Message-ID: <ZBHudqNmLVsCg4JQ@bombadil.infradead.org> (raw)
In-Reply-To: <18363c7d-ddec-df1a-8a8e-dd5321499545@suse.com>

On Wed, Mar 15, 2023 at 03:43:54PM +0100, Petr Pavlu wrote:
> 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.

Ah then nevermind then thanks! I'll be sure to document this moving
forwward!

> 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?

The idea was an old one and if it could help, but the above makes the
idea useless, and so the only value for these aliases in-kernel could be
for debugging, that's all.

Removing this will also simplify this patch series anyway.

  Luis

  reply	other threads:[~2023-03-15 16:13 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-11  5:17 [RFC 00/12] module: avoid userspace pressure on unwanted allocations Luis Chamberlain
2023-03-11  5:17 ` [RFC 01/12] module: use goto errors on check_modinfo() and layout_and_allocate() Luis Chamberlain
2023-03-11  5:17 ` [RFC 02/12] module: move get_modinfo() helpers all above Luis Chamberlain
2023-03-11  5:17 ` [RFC 03/12] module: rename next_string() to module_next_tag_pair() Luis Chamberlain
2023-03-11  5:17 ` [RFC 04/12] module: add a for_each_modinfo_entry() Luis Chamberlain
2023-03-11  5:17 ` [RFC 05/12] module: add debugging alias parsing support Luis Chamberlain
2023-03-11  5:17 ` [RFC 06/12] module: move early sanity checks into a helper Luis Chamberlain
2023-03-11  5:17 ` [RFC 07/12] module: move check_modinfo() early to early_mod_check() Luis Chamberlain
2023-03-11  5:17 ` [RFC 08/12] module: move finished_loading() Luis Chamberlain
2023-03-11  5:17 ` [RFC 09/12] module: extract patient module check into helper Luis Chamberlain
2023-03-11  5:17 ` [RFC 10/12] module: avoid allocation if module is already present and ready Luis Chamberlain
2023-03-11  5:17 ` [RFC 11/12] module: use list_add_tail_rcu() when adding module Luis Chamberlain
2023-03-11  5:17 ` [RFC 12/12] module: use aliases to find module on find_module_all() Luis Chamberlain
2023-03-11 13:12   ` kernel test robot
2023-03-11 17:06   ` kernel test robot
2023-03-15 14:43   ` Petr Pavlu
2023-03-15 16:12     ` Luis Chamberlain [this message]
2023-03-15 12:24 ` [RFC 00/12] module: avoid userspace pressure on unwanted allocations David Hildenbrand
2023-03-15 16:10   ` Luis Chamberlain
2023-03-15 16:41     ` David Hildenbrand
2023-03-16 23:55       ` Luis Chamberlain
2023-03-16 23:56         ` Luis Chamberlain
2023-03-18  0:11           ` Luis Chamberlain
2023-03-20  9:38             ` David Hildenbrand
2023-03-20 19:40               ` David Hildenbrand
2023-03-20 21:09                 ` Luis Chamberlain
2023-03-20 21:15                   ` David Hildenbrand
2023-03-20 21:23                     ` Luis Chamberlain
2023-03-20 21:27                       ` Luis Chamberlain
2023-03-21 19:32                         ` David Hildenbrand
2023-03-24  9:27                           ` David Hildenbrand
2023-03-24 17:54                             ` Luis Chamberlain
2023-03-24 19:11                               ` Linus Torvalds
2023-03-24 19:59                                 ` Luis Chamberlain
2023-03-24 20:28                                   ` Linus Torvalds
2023-03-24 21:14                                     ` Luis Chamberlain
2023-03-24 23:27                                       ` Luis Chamberlain
2023-03-24 23:41                                         ` Linus Torvalds
2023-03-28  3:44                               ` David Hildenbrand
2023-03-28  6:16                                 ` Luis Chamberlain
2023-03-28 21:02                                   ` David Hildenbrand
2023-03-29  5:31                                     ` Luis Chamberlain
2023-03-30  4:42                                       ` David Hildenbrand
2023-03-21 15:11                       ` David Hildenbrand
2023-03-21 16:52                         ` Luis Chamberlain
2023-03-21 17:01                           ` David Hildenbrand
2023-03-20  9:37           ` David Hildenbrand

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