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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Wed, 17 Aug 2022 23:44:53 +0200
Message-ID: <CANiq72=6nzbMR1e=7HUAotPk-L00h0YO3-oYrtKy2BLcHVDTEw@mail.gmail.com>
Subject: Re: [PATCH v9 06/27] rust: add C helpers
To:     Kees Cook <keescook@chromium.org>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, patches@lists.linux.dev,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Geoffrey Thomas <geofft@ldpreload.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        Sven Van Asbroeck <thesven73@gmail.com>,
        Gary Guo <gary@garyguo.net>, Boqun Feng <boqun.feng@gmail.com>,
        Maciej Falkowski <m.falkowski@samsung.com>,
        Wei Liu <wei.liu@kernel.org>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>
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On Wed, Aug 17, 2022 at 10:34 PM Kees Cook <keescook@chromium.org> wrote:
>
> Gotcha -- it's for the implicit situations (e.g. -C overflow-checks=on),

Yeah, exactly.

> nothing is expected to explicitly call the Rust panic handler?

If by explicitly you mean calling `panic!()`, then in the `kernel`
crate in the v9 patches there is none.

Though we may want to call it in the future (we have 4 instances in
the full code not submitted here, e.g. for mismatching an independent
lock guard with its owner). They can be avoided depending on how we
want the design to be and, I guess, what the "Rust panic" policy will
finally be (i.e. `BUG()` or something softer).

Outside the `kernel` crate, there are also instances in proc macros
and Rust hostprogs/scripts (compilation-time in the host), in the
`alloc` crate (compiled-out) and in the `compiler_builtins` crate (for
e.g. `u128` support that eventually we would like to not see
compiled-in).

Cheers,
Miguel