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Date:   Sun, 30 Jul 2023 22:41:54 +0000
To:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
From:   =?utf-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>
Cc:     Boqun Feng <boqun.feng@gmail.com>, rust-for-linux@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Gary Guo <gary@garyguo.net>,
        Benno Lossin <benno.lossin@proton.me>,
        Martin Rodriguez Reboredo <yakoyoku@gmail.com>,
        Alice Ryhl <aliceryhl@google.com>,
        Dariusz Sosnowski <dsosnowski@dsosnowski.pl>,
        Geoffrey Thomas <geofft@ldpreload.com>,
        Fox Chen <foxhlchen@gmail.com>,
        John Baublitz <john.m.baublitz@gmail.com>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        Kees Cook <keescook@chromium.org>, stable@vger.kernel.org,
        Andreas Hindborg <nmi@metaspace.dk>
Subject: Re: [PATCH 1/3] rust: allocator: Prevent mis-aligned allocation
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On Jul 30, 2023, 10:43 PM, Miguel Ojeda < miguel.ojeda.sandonis@gmail.com> =
wrote:
> On Sun, Jul 30, 2023 at 3:29=E2=80=AFAM Boqun > Feng <boqun.feng@gmail.co=
m> wrote:
> >
> > +// Note: Although these are *safe* functions, but they are only genera=
ted at
> > +// `GlobalAlloc` callsites, hence we assume the parameters obey the sa=
me
> > +// `GlobalAlloc` function safety requirements: size and align should f=
orm a
> > +// valid layout, and size is greater than 0.
>
> Thanks for adding all the `// SAFETY` comments here Boqun!
>
> Bj=C3=B6rn, do they look good to you? (since you fixed the issue in the c=
ompiler)

Based on a quick look, yes. The __rust_* methods that are normally generate=
d by the compiled directly jump to the respective global allocator method, =
so they have the same safety requirements.

>
> On this comment in particular, "generated at `GlobalAlloc` callsites"
sounds a bit confusing to me. Would "... called by the compiler with
parameters that obey ..." make sense? Or does the sentence refer to
the normal case (i.e. when the functions are generated)? Anyway, it is
not a big deal.
>
> Cheers,
> Miguel

Cheers,
Bj=C3=B6rn

(resent as I accidentally sent html instead of plain text)