linux-kernel - Re: [PATCH v9 8/8] task: rust: rework how current is accessed

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: <CAH5fLgippKab6Qarc7go8pz8XPrvEOoi_FvzMNAJXzr8v3qqjA@mail.gmail.com>
Date: Fri, 22 Nov 2024 20:43:33 +0100
From: Alice Ryhl <aliceryhl@...gle.com>
To: Matthew Wilcox <willy@...radead.org>
Cc: Boqun Feng <boqun.feng@...il.com>, Miguel Ojeda <ojeda@...nel.org>, 
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, Vlastimil Babka <vbabka@...e.cz>, 
	John Hubbard <jhubbard@...dia.com>, "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Arnd Bergmann <arnd@...db.de>, Christian Brauner <brauner@...nel.org>, Jann Horn <jannh@...gle.com>, 
	Suren Baghdasaryan <surenb@...gle.com>, Alex Gaynor <alex.gaynor@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <benno.lossin@...ton.me>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	rust-for-linux@...r.kernel.org, Andreas Hindborg <a.hindborg@...nel.org>
Subject: Re: [PATCH v9 8/8] task: rust: rework how current is accessed

On Fri, Nov 22, 2024 at 8:30 PM Matthew Wilcox <willy@...radead.org> wrote:
>
> On Fri, Nov 22, 2024 at 11:17:15AM -0800, Boqun Feng wrote:
> > > I don't think this is a problem? As long as a thread exists somewhere
> > > with `current` being equal to the task, we should be fine?
> > >
> >
> > I think I had a misunderstanding on what you meant by "operations
> > that are only valid on the current task", you mean these operations can
> > be run by other threads, but it has to be *on* a task_struct that's
> > "currently running", right? BTW, you probably want to reword a bit,
> > because the "current" task may be blocked, so technically it's not
> > "running".
> >
> > Basically, the operations that `CurrentTask` have are the methods that
> > are safe to call (even on a different thread) for the "current" task, as
> > long as it exists (not dead or exited). In that definition, not being
> > `Sync` is fine.
> >
> > But I have to admit I'm a bit worried that people may be confused, and
> > add new methods that can be only run by the current thread in the
> > future.
>
> I agree, I think CurrentTask should refer to "current".  Or we'll
> confuse everyone.  Would ActiveTask be a good name for this CurrentTask?

I mean, it does refer to current. Any time you have a `&CurrentTask`,
then you know that you got the pointer by reading the value of
`current`, and that the task you got it from hasn't returned to
userspace (or otherwise exited) yet.

But the name ActiveTask also makes sense I guess.

Alice