Re: [PATCH v2 3/4] arch: copy_thread: pass clone_flags as u64

Andreas Larsson
2025-09-02T07:02:50Z

On 2025-09-01 15:09, Simon Schuster via B4 Relay wrote:
> From: Simon Schuster <schuster.simon@siemens-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@siemens-energy.com>
> ---

Thanks for this and for the whole series! Needed foundation for a
sparc32 clone3 implementation as well.

> arch/sparc/kernel/process_32.c | 2 +-
> arch/sparc/kernel/process_64.c | 2 +-

Acked-by: Andreas Larsson <andreas@gaisler.com> # sparc

Cheers,
Andreas