Message-ID: <ffb22e54-6b7d-5b88-4217-e67870051c6e@kernel.org>
Date: Thu, 18 Sep 2025 09:51:07 -0600 (MDT)
From: Paul Walmsley <pjw@...nel.org>
To: Simon Schuster <schuster.simon@...mens-energy.com>
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Subject: Re: [PATCH v2 3/4] arch: copy_thread: pass clone_flags as u64

On Mon, 1 Sep 2025, Simon Schuster via B4 Relay wrote:

> From: Simon Schuster <schuster.simon@...mens-energy.com>
> 
> With the introduction of clone3 in commit 7f192e3cd316 ("fork: add
> clone3") the effective bit width of clone_flags on all architectures was
> increased from 32-bit to 64-bit, with a new type of u64 for the flags.
> However, for most consumers of clone_flags the interface was not
> changed from the previous type of unsigned long.
> 
> While this works fine as long as none of the new 64-bit flag bits
> (CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still
> undesirable in terms of the principle of least surprise.
> 
> Thus, this commit fixes all relevant interfaces of the copy_thread
> function that is called from copy_process to consistently pass
> clone_flags as u64, so that no truncation to 32-bit integers occurs on
> 32-bit architectures.
> 
> Signed-off-by: Simon Schuster <schuster.simon@...mens-energy.com>

Acked-by: Paul Walmsley <pjw@...nel.org> # for RISC-V

Thanks!


- Paul

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