Re: [PATCH v2 3/4] arch: copy_thread: pass clone_flags as u64
From: Paul Walmsley <pjw@kernel.org>
Date: 2025-09-18 15:51:17
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On Mon, 1 Sep 2025, 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>Acked-by: Paul Walmsley <pjw@kernel.org> # for RISC-V Thanks! - Paul