linux-kernel - Re: [PATCH] rust: task: adjust safety comments in Task methods

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] [day] [month] [year] [list]

Message-ID: <54f1e546-1fe0-40f7-87e6-109006b762a6@ryhl.io>
Date: Tue, 15 Oct 2024 20:53:45 +0200
From: Alice Ryhl <alice@...l.io>
To: Boqun Feng <boqun.feng@...il.com>
Cc: Alice Ryhl <aliceryhl@...gle.com>, Christian Brauner
 <brauner@...nel.org>, Miguel Ojeda <ojeda@...nel.org>,
 Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
 Alex Gaynor <alex.gaynor@...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-fsdevel@...r.kernel.org, rust-for-linux@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rust: task: adjust safety comments in Task methods

On 10/15/24 8:45 PM, Boqun Feng wrote:
> On Tue, Oct 15, 2024 at 08:37:36PM +0200, Alice Ryhl wrote:
>> On 10/15/24 8:24 PM, Boqun Feng wrote:
>>> On Tue, Oct 15, 2024 at 02:02:12PM +0000, Alice Ryhl wrote:
>>>> The `Task` struct has several safety comments that aren't so great. For
>>>> example, the reason that it's okay to read the `pid` is that the field
>>>> is immutable, so there is no data race, which is not what the safety
>>>> comment says.
>>>>
>>>> Thus, improve the safety comments. Also add an `as_ptr` helper. This
>>>> makes it easier to read the various accessors on Task, as `self.0` may
>>>> be confusing syntax for new Rust users.
>>>>
>>>> Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>
>>>> ---
>>>> This is based on top of vfs.rust.file as the file series adds some new
>>>> task methods. Christian, can you take this through that tree?
>>>> ---
>>>>    rust/kernel/task.rs | 43 ++++++++++++++++++++++++-------------------
>>>>    1 file changed, 24 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
>>>> index 1a36a9f19368..080599075875 100644
>>>> --- a/rust/kernel/task.rs
>>>> +++ b/rust/kernel/task.rs
>>>> @@ -145,11 +145,17 @@ fn deref(&self) -> &Self::Target {
>>>>            }
>>>>        }
>>>> +    /// Returns a raw pointer to the task.
>>>> +    #[inline]
>>>> +    pub fn as_ptr(&self) -> *mut bindings::task_struct {
>>>
>>> FWIW, I think the name convention is `as_raw()` for a wrapper type of
>>> `Opaque<T>` to return `*mut T`, e.g. `kernel::device::Device`.
>>>
>>> Otherwise this looks good to me.
>> Both names are in use. See e.g. Page and File that use as_ptr.
>>
> 
> `Page` is a different case because it currently is a pointer.
> 
>> In fact, I was asked to change the name on File *to* as_ptr.
>>
> 
> I'm not able to find the discussion on that ask. Appreciate it if you
> can share a link.

Hmm, it's possible that I misremember. I can't find it either. But it is 
called as_ptr on File.

> Anyway, this is not important for now, and might not be in the future.
> So:
> 
> Reviewed-by: Boqun Feng <boqun.feng@...il.com>

Thanks!

Alice