linux-kernel - Re: [PATCH] rust: irq: add support for request

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: <04864DC4-FA5B-4D7A-8EE5-BDA1E8F88007@collabora.com>
Date: Tue, 14 Jan 2025 15:34:56 -0300
From: Daniel Almeida <daniel.almeida@...labora.com>
To: Alice Ryhl <aliceryhl@...gle.com>
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>,
 Benno Lossin <benno.lossin@...ton.me>,
 Andreas Hindborg <a.hindborg@...nel.org>,
 Trevor Gross <tmgross@...ch.edu>,
 linux-kernel@...r.kernel.org,
 rust-for-linux@...r.kernel.org
Subject: Re: [PATCH] rust: irq: add support for request_irq()

Hi Alice,

> On 13 Jan 2025, at 11:42, Alice Ryhl <aliceryhl@...gle.com> wrote:
> 
> On Thu, Oct 24, 2024 at 4:20 PM Daniel Almeida
> <daniel.almeida@...labora.com> wrote:
>> 
>> +impl<T: Handler> Registration<T> {
>> +    /// Registers the IRQ handler with the system for the given IRQ number. The
>> +    /// handler must be able to be called as soon as this function returns.
>> +    pub fn register(
>> +        irq: u32,
>> +        flags: Flags,
>> +        name: &'static CStr,
>> +        handler: T,
>> +    ) -> impl PinInit<Self, Error> {
>> +        try_pin_init!(Self {
>> +            irq,
>> +            handler: Opaque::new(handler)
>> +        })
>> +        .pin_chain(move |slot| {
>> +            // SAFETY:
>> +            // - `handler` points to a valid function defined below.
>> +            // - only valid flags can be constructed using the `flags` module.
>> +            // - `devname` is a nul-terminated string with a 'static lifetime.
>> +            // - `ptr` is a cookie used to identify the handler. The same cookie is
>> +            // passed back when the system calls the handler.
>> +            to_result(unsafe {
>> +                bindings::request_irq(
>> +                    irq,
>> +                    Some(handle_irq_callback::<T>),
>> +                    flags.0,
>> +                    name.as_char_ptr(),
>> +                    &*slot as *const _ as *mut core::ffi::c_void,
>> +                )
>> +            })?;
>> +
>> +            Ok(())
>> +        })
> 
> I think this does not run the destructor of `handler` when
> `request_irq` returns an error.
> 
> Alice

How? T is passed by value, so if request_irq() fails and thus Registration::register() returns Err,
I assume T is dropped.

Or is the pin_init! stuff somehow special here?

— Daniel