| From: |
| Andrei Vagin <avagin-AT-google.com> |
| To: |
| Kees Cook <kees-AT-kernel.org> |
| Subject: |
| [PATCH 0/3 v2] exec: inherit HWCAPs from the parent process |
| Date: |
| Thu, 08 Jan 2026 05:07:45 +0000 |
| Message-ID: |
| <20260108050748.520792-1-avagin@google.com> |
| Cc: |
| linux-kernel-AT-vger.kernel.org, linux-fsdevel-AT-vger.kernel.org, linux-mm-AT-kvack.org, criu-AT-lists.linux.dev, Andrew Morton <akpm-AT-linux-foundation.org>, Chen Ridong <chenridong-AT-huawei.com>, Christian Brauner <brauner-AT-kernel.org>, David Hildenbrand <david-AT-kernel.org>, Eric Biederman <ebiederm-AT-xmission.com>, Lorenzo Stoakes <lorenzo.stoakes-AT-oracle.com>, Michal Koutny <mkoutny-AT-suse.com> |
This patch series introduces a mechanism to inherit hardware capabilities
(AT_HWCAP, AT_HWCAP2, etc.) from a parent process when they have been
modified via prctl.
To support C/R operations (snapshots, live migration) in heterogeneous
clusters, we must ensure that processes utilize CPU features available
on all potential target nodes. To solve this, we need to advertise a
common feature set across the cluster.
Initially, a cgroup-based approach was considered, but it was decided
that inheriting HWCAPs from a parent process that has set its own
auxiliary vector via prctl is a simpler and more flexible solution.
This implementation adds a new mm flag MMF_USER_HWCAP, which is set when the
auxiliary vector is modified via prctl(PR_SET_MM_AUXV). When execve() is
called, if the current process has MMF_USER_HWCAP set, the HWCAP values are
extracted from the current auxiliary vector and inherited by the new process.
The first patch fixes AUXV size calculation for ELF_HWCAP3 and ELF_HWCAP4
in binfmt_elf_fdpic and updates AT_VECTOR_SIZE_BASE.
The second patch implements the core inheritance logic in execve().
The third patch adds a selftest to verify that HWCAPs are correctly
inherited across execve().
v1: https://lkml.org/lkml/2025/12/5/65
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Koutny <mkoutny@suse.com>
Andrei Vagin (3):
binfmt_elf_fdpic: fix AUXV size calculation for ELF_HWCAP3 and ELF_HWCAP4
exec: inherit HWCAPs from the parent process
selftests/exec: add test for HWCAP inheritance
fs/binfmt_elf.c | 8 +-
fs/binfmt_elf_fdpic.c | 14 ++-
fs/exec.c | 58 +++++++++++
include/linux/auxvec.h | 2 +-
include/linux/binfmts.h | 11 ++
include/linux/mm_types.h | 2 +
kernel/fork.c | 3 +
kernel/sys.c | 5 +-
tools/testing/selftests/exec/.gitignore | 1 +
tools/testing/selftests/exec/Makefile | 1 +
tools/testing/selftests/exec/hwcap_inherit.c | 102 +++++++++++++++++++
11 files changed, 197 insertions(+), 10 deletions(-)
create mode 100644 tools/testing/selftests/exec/hwcap_inherit.c
--
2.52.0.351.gbe84eed79e-goog
