Re: [PATCH v2 2/4] copy_process: pass clone_flags as u64 across calltree
From: "Arnd Bergmann" <arnd@arndb.de>
Date: 2025-09-01 13:35:31
Also in:
cgroups, linux-alpha, linux-block, linux-fsdevel, linux-m68k, linux-mips, linux-mm, linux-perf-users, linux-riscv, linux-s390, linux-security-module, linux-sh, linux-trace-kernel, linux-um, lkml, loongarch, netdev, selinux, sparclinux
On Mon, Sep 1, 2025, at 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 callees to
sys_clone3/copy_process (excluding the architecture-specific
copy_thread) 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>
Reviewed-by: Lorenzo Stoakes <redacted>Reviewed-by: Arnd Bergmann <arnd@arndb.de>