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Mon, 23 Feb 2026 10:29:11 -0800 (PST) MIME-Version: 1.0 References: <20260217180108.1420024-1-avagin@google.com> In-Reply-To: <20260217180108.1420024-1-avagin@google.com> From: Andrei Vagin Date: Mon, 23 Feb 2026 10:29:00 -0800 X-Gm-Features: AaiRm516DL4wdtFRf7EQJjraaJNo9amL-ln10-8gw16pLLQ7cUL2md0iZsvWpvk Message-ID: Subject: Re: [PATCH 0/4 v4] exec: inherit HWCAPs from the parent process To: Kees Cook Cc: Andrew Morton , 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 , Andrei Vagin Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 62FC540007 X-Stat-Signature: ba6f187t5xrcnwde5if1xojh9cz1rn8j X-HE-Tag: 1771871352-520738 X-HE-Meta: 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 H8zOchvI uDzT8pTBAIvjmWJ/lF9wlTAu4pTOYS2cj5p3vdl7Rmvtv7zTFPgsZH7S9zx6pJT0C3jL3AxJWCKQYo2OouY4DsnULx72CVTFAc7W/Cj2N4PnQnyjQEohyWBsVWsxnaArtDDn671E2hq3/H9NlVhm3QN38wiQLKl0Moou5mbxgBMD70ITIEt7hkSJekHfvW2dnOHXp1lixms/iLDaYKRn5NC49z7NQNf17k9ialXLY5vCOjShMkOzIMNu9Mk6AtX6Sq1Quncgf0rpWxmpPj4JpCrXmqD63kUjbct/DHc3zkGXVl4xCbboyHFGV73KngZHpiEE3WpItFOilexQPIALOq3dVu1Li3xINp2hjw/D6rxlxXL/V7JGhzJ54iVe8QqKATJSwui0wv01pxAuUgMqmKzTnx0rB761JmfGu5S8M/vhjv7Y= 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: On Tue, Feb 17, 2026 at 10:01=E2=80=AFAM Andrei Vagin w= rote: > > 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 a= re > extracted from the current auxiliary vector and inherited by the new proc= ess. > > 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. Kees, I think it is ready to be merged. Let me know if you have any other comments/concerns/questions. Thanks, Andrei