netdev - Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

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: <CAH5fLggyhvEhQL_VWdd38QyFuegPY5mXY_J-jZrh9w8=WPb2Vg@mail.gmail.com>
Date: Wed, 31 Jul 2024 14:32:18 +0200
From: Alice Ryhl <aliceryhl@...gle.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: FUJITA Tomonori <fujita.tomonori@...il.com>, netdev@...r.kernel.org, 
	rust-for-linux@...r.kernel.org, tmgross@...ch.edu, 
	miguel.ojeda.sandonis@...il.com, benno.lossin@...ton.me
Subject: Re: [PATCH net-next v2 2/6] rust: net::phy support probe callback

On Wed, Jul 31, 2024 at 2:24 PM Andrew Lunn <andrew@...n.ch> wrote:
>
> On Wed, Jul 31, 2024 at 01:21:32PM +0900, FUJITA Tomonori wrote:
> > Support phy_driver probe callback, used to set up device-specific
> > structures.
> >
> > Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
> > ---
> >  rust/kernel/net/phy.rs | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> > index fd40b703d224..99a142348a34 100644
> > --- a/rust/kernel/net/phy.rs
> > +++ b/rust/kernel/net/phy.rs
> > @@ -338,6 +338,20 @@ impl<T: Driver> Adapter<T> {
> >          })
> >      }
> >
> > +    /// # Safety
> > +    ///
> > +    /// `phydev` must be passed by the corresponding callback in `phy_driver`.
> > +    unsafe extern "C" fn probe_callback(phydev: *mut bindings::phy_device) -> core::ffi::c_int {
> > +        from_result(|| {
> > +            // SAFETY: This callback is called only in contexts
> > +            // where we can exclusively access to `phy_device`, so the accessors on
> > +            // `Device` are okay to call.
>
> This one is slightly different to other callbacks. probe is called
> without the mutex. Instead, probe is called before the device is
> published. So the comment is correct, but given how important Rust
> people take these SAFETY comments, maybe it should indicate it is
> different to others?

Interesting. Given that we don't hold the mutex, does that mean that
some of the methods on Device are not safe to call in this context? Or
is there something else that makes it okay to call them despite not
holding the mutex?

Alice