linux-kernel - Re: [PATCH] rust: Do not export generated KASAN ODR symbols

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Message-ID: <CANiq72nr9vTgUF9u0uyypzprQrEpGv4qbOUJS_QgYbMZhTTrRQ@mail.gmail.com>
Date: Wed, 22 Jan 2025 10:11:48 +0100
From: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To: Matthew Maurer <mmaurer@...gle.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	Boqun Feng <boqun.feng@...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>, 
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rust: Do not export generated KASAN ODR symbols

On Wed, Jan 22, 2025 at 1:14 AM Matthew Maurer <mmaurer@...gle.com> wrote:
>
> ASAN generates sppecial synthetic symbols to help check for ODR
> violations. These synthetic symbols lack debug information, so
> gendwarfksyms emits warnings when processing them. No code should ever
> have a dependency on these symbols, so we should not be exporting them,
> just like the __cfi symbols.
>
> Signed-off-by: Matthew Maurer <mmaurer@...gle.com>

Sounds good -- are those generated unconditionally by ASAN to check
for C++ ODR violations and so we get them anyway or do we benefit
somehow?

I also wondered about whether we should search for an extra underscore
(`__odr_asan_`), but I also see mentions of `__odr_asan.`, which I
guess that is the reason you used that prefix. Is that right?

Acked-by: Miguel Ojeda <ojeda@...nel.org>

Thanks!

Cheers,
Miguel