linux-kernel - Re: [PATCH v13 4/6] rust: module: update the module macro with module parameter support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87plez7w18.fsf@kernel.org>
Date: Thu, 19 Jun 2025 14:31:15 +0200
From: Andreas Hindborg <a.hindborg@...nel.org>
To: "Benno Lossin" <lossin@...nel.org>
Cc: "Miguel Ojeda" <ojeda@...nel.org>,  "Alex Gaynor"
 <alex.gaynor@...il.com>,  "Boqun Feng" <boqun.feng@...il.com>,  "Gary Guo"
 <gary@...yguo.net>,  Björn Roy Baron
 <bjorn3_gh@...tonmail.com>,  "Alice
 Ryhl" <aliceryhl@...gle.com>,  "Masahiro Yamada" <masahiroy@...nel.org>,
  "Nathan Chancellor" <nathan@...nel.org>,  "Luis Chamberlain"
 <mcgrof@...nel.org>,  "Danilo Krummrich" <dakr@...nel.org>,  "Nicolas
 Schier" <nicolas.schier@...ux.dev>,  "Trevor Gross" <tmgross@...ch.edu>,
  "Adam Bratschi-Kaye" <ark.email@...il.com>,
  <rust-for-linux@...r.kernel.org>,  <linux-kernel@...r.kernel.org>,
  <linux-kbuild@...r.kernel.org>,  "Petr Pavlu" <petr.pavlu@...e.com>,
  "Sami Tolvanen" <samitolvanen@...gle.com>,  "Daniel Gomez"
 <da.gomez@...sung.com>,  "Simona Vetter" <simona.vetter@...ll.ch>,  "Greg
 KH" <gregkh@...uxfoundation.org>,  "Fiona Behrens" <me@...enk.dev>,
  "Daniel Almeida" <daniel.almeida@...labora.com>,
  <linux-modules@...r.kernel.org>
Subject: Re: [PATCH v13 4/6] rust: module: update the module macro with
 module parameter support

"Benno Lossin" <lossin@...nel.org> writes:

> On Thu Jun 12, 2025 at 3:40 PM CEST, Andreas Hindborg wrote:
>> +
>> +    fn emit_params(&mut self, info: &ModuleInfo) {
>> +        let Some(params) = &info.params else {
>> +            return;
>> +        };
>> +
>> +        for param in params {
>> +            let ops = param_ops_path(&param.ptype);
>> +
>> +            // Note: The spelling of these fields is dictated by the user space
>> +            // tool `modinfo`.
>> +            self.emit_param("parmtype", &param.name, &param.ptype);
>> +            self.emit_param("parm", &param.name, &param.description);
>
> I just read this part again and I want to voice my dissatisfaction with
> these key names. (not that you can do anything about that :)
>
>> +
>> +            write!(
>> +                self.param_buffer,
>> +                "
>> +                    pub(crate) static {param_name}:
>
> Does this need to be accessed by anything else except the static below?
> If no, then can we move it inside of that static? So
>
>     #[link_section = \"__param\"]
>     #[used]
>     static __{module_name}_{param_name}_struct: ::kernel::module_param::RacyKernelParam = {
>         static {param_name}:
>             ::kernel::module_param::ModuleParamAccess<{param_type}> =
>                 ::kernel::module_param::ModuleParamAccess::new({param_default});
>         // ...
>     };

It is used to access the value of the parameter from the module. If you
reduce visibility you will get an error when trying to read the
parameter value:

    RUSTC     samples/rust/rust_minimal.o
  error[E0425]: cannot find value `test_parameter` in module `module_parameters`
    --> /home/aeh/src/linux-rust/module-params/samples/rust/rust_minimal.rs:31:33
    |
  31 |             *module_parameters::test_parameter.get()
    |                                 ^^^^^^^^^^^^^^ not found in `module_parameters`

  error: aborting due to 1 previous error


Best regards,
Andreas Hindborg