linux-kernel - Re: [PATCH v2] gendwarfksyms: Skip files with no exports

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: <CABCJKuc0ZwN23MX4mV=vVne1giR=iWKSvqFg1oKMqxUcnOWiCg@mail.gmail.com>
Date: Tue, 18 Nov 2025 08:26:13 -0800
From: Sami Tolvanen <samitolvanen@...gle.com>
To: Giuliano Procida <gprocida@...gle.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	linux-modules@...r.kernel.org, linux-kbuild@...r.kernel.org, 
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, 
	Danilo Krummrich <dakr@...nel.org>, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org, patches@...ts.linux.dev, stable@...r.kernel.org, 
	Haiyue Wang <haiyuewa@....com>
Subject: Re: [PATCH v2] gendwarfksyms: Skip files with no exports

Hi Giuliano,

On Tue, Nov 18, 2025 at 6:58 AM Giuliano Procida <gprocida@...gle.com> wrote:
>
> Hi.
>
> > Thus do the last one: don't attempt to process files if we have no symbol
> > versions to calculate.
>
> This results in the -T foo option being ignored in the case there were
> no symbols. I think it would be better, consistent with the
> documentation and expectations, for the file to be produced empty.

The kernel build doesn't produce empty symtypes files because symbol
versioning is skipped for (non-Rust) object files that have no
exports, and before rustc 1.91, we never ran gendwarfksyms for Rust
object files that didn't have exports.

> This means that just the for loop should be skipped, say by adding the
> condition there with &&.

No, I think the current behavior is correct, we shouldn't produce empty files.

> If you disagree, then please update the documentation to match the new
> behaviour.

I re-read the documentation and it doesn't really state how the -T
flag behaves if the tool is used to process a file with no exports.
While this doesn't impact kernel builds, a patch to clarify the
documentation is always welcome!

Sami