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AJvYcCX6A9CI3X8vIWbf5zjemzpg4rH51XuQU5MCZsLMS+R8mhYOAfqNChlGPHmNXYhHWccV2l5Z56o96g==@kvack.org X-Gm-Message-State: AOJu0YzuCyzaD7ft35dYsR1XNoAufgiIj0orRha3RW8o5CrGcILVzXs/ QUurw8TPugWOndJdSHq8lSY//B0k/Q8Ol4bbTwwYRm9LBetSyNmZ6IYbLFDeQzvPfXsp1Wvk8iR nK2HwNg== X-Received: from jabki4.prod.google.com ([2002:a05:6638:a804:b0:5ca:ff1f:79f]) (user=avagin job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6820:4b01:b0:679:a4bc:9f8f with SMTP id 006d021491bc7-679a4bca251mr287501eaf.61.1771351271099; Tue, 17 Feb 2026 10:01:11 -0800 (PST) Date: Tue, 17 Feb 2026 18:01:04 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.310.g728cabbaf7-goog Message-ID: <20260217180108.1420024-1-avagin@google.com> Subject: [PATCH 0/4 v4] exec: inherit HWCAPs from the parent process From: Andrei Vagin To: Kees Cook , Andrew Morton Cc: Cyrill Gorcunov , Mike Rapoport , Alexander Mikhalitsyn , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, criu@lists.linux.dev, Chen Ridong , Christian Brauner , David Hildenbrand , Eric Biederman , Lorenzo Stoakes , Michal Koutny Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 9injmycnsng9io5ukf1gmb4saqrpgf4t X-Rspamd-Server: rspam11 X-Rspam-User: X-Rspamd-Queue-Id: AA4974001D X-HE-Tag: 1771351272-671572 X-HE-Meta: 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 ntvC3r9n Gzsqd5TVn4ai3cxxzpHwwOAVooOJR7I93mgBghzYrGN7hcZhKtB5+vtkcaZq+VplCJHCI68GyK4eyUvY+jE1Fy8hC9kdcVVKQOrJK8olRq+EQWNzckox1mnskBRc0HUGlawHgqwiFMG+r2lqsLGvoT8sExZjE8g+WdaYX3kd6mw0d098aj46JLnVwG/zLDy4t06cQPcvfamOWBa6OWZyhtJCM31UKPc85BvpaWhUgnzBB4tNI3kZMjlOfNos75L8fGzYKoL+RAPBc4BzcIwxaun2QcEsegJviuDSHrID62cq70TOuMH0OYrVMLYkpbcnQy9WrICi0Tj8VwSWpCnNLyJLMxQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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(). v4: minor fixes based on feedback from the previous version. v3: synchronize saved_auxv access with arg_lock v1: https://lkml.org/lkml/2025/12/5/65 v2: https://lkml.org/lkml/2026/1/8/219 v3: https://lkml.org/lkml/2026/2/9/1233 Cc: Andrew Morton Cc: Chen Ridong Cc: Christian Brauner Cc: David Hildenbrand Cc: Eric Biederman Cc: Kees Cook Cc: Lorenzo Stoakes Cc: Michal Koutny Cc: Cyrill Gorcunov Andrei Vagin (3): binfmt_elf_fdpic: fix AUXV size calculation for ELF_HWCAP3 and ELF_HWCAP4 exec: inherit HWCAPs from the parent process mm: synchronize saved_auxv access with arg_lock selftests/exec: add test for HWCAP inheritance fs/binfmt_elf.c | 8 +- fs/binfmt_elf_fdpic.c | 14 ++- fs/exec.c | 64 ++++++++++++ fs/proc/base.c | 12 ++- include/linux/auxvec.h | 2 +- include/linux/binfmts.h | 11 ++ include/linux/mm_types.h | 2 + kernel/fork.c | 8 ++ kernel/sys.c | 30 +++--- tools/testing/selftests/exec/.gitignore | 1 + tools/testing/selftests/exec/Makefile | 1 + tools/testing/selftests/exec/hwcap_inherit.c | 104 +++++++++++++++++++ 12 files changed, 231 insertions(+), 26 deletions(-) create mode 100644 tools/testing/selftests/exec/hwcap_inherit.c -- 2.52.0.351.gbe84eed79e-goog