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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Wed, 14 Apr 2021 21:50:35 +0200
Message-ID: <CANiq72=VnWEdh2uuwH2JM6ZhrEVDiQisnNBQGX-qwPnTitcR=g@mail.gmail.com>
Subject: Re: [PATCH 07/13] Rust: Kernel crate
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rust-for-linux@vger.kernel.org,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Geoffrey Thomas <geofft@ldpreload.com>,
        Finn Behrens <me@kloenk.de>,
        Adam Bratschi-Kaye <ark.email@gmail.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        Michael Ellerman <mpe@ellerman.id.au>
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On Wed, Apr 14, 2021 at 9:31 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Again, excuse my lack of internal Rust knowledge, but when do these
> end up being an issue?
>
> If the Rust compiler ends up doing hidden allocations, and they then
> cause panics, then one of the main *points* of Rustification is
> entirely broken. That's 100% the opposite of being memory-safe at
> build time.

Of course! What happens here is that we use, for the moment, `alloc`,
which is part of the Rust standard library. However, we will be
customizing/rewriting `alloc` as needed to customize its types (things
like `Box`, `Vec`, etc.) so that we can do things like pass allocation
flags, ensure we always have fallible allocations, perhaps reuse some
of the kernel data structures, etc.

Cheers,
Miguel