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

John Paul Adrian Glaubitz
2025-09-02T07:15:22Z

Hi Andreas,

On Tue, 2025-09-02 at 09:02 +0200, Andreas Larsson wrote:
> 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.

Can you implement clone3 for sparc64 as well?

Adrian

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