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Tue, 10 Feb 2026 11:28:10 -0800 (PST) Received: by grain.localdomain (Postfix, from userid 1000) id 8CBD35A004A; Tue, 10 Feb 2026 22:28:06 +0300 (MSK) Date: Tue, 10 Feb 2026 22:28:06 +0300 From: Cyrill Gorcunov To: Andrei Vagin Cc: Kees Cook , Andrew Morton , 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 Subject: Re: [PATCH 0/4 v3] exec: inherit HWCAPs from the parent process Message-ID: References: <20260209190605.1564597-1-avagin@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260209190605.1564597-1-avagin@google.com> User-Agent: Mutt/2.2.14 (2025-02-20) On Mon, Feb 09, 2026 at 07:06:01PM +0000, Andrei Vagin wrote: > 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(). > > 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 > > 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 Looks ok to me. Thanks, Andrei! Reviewed-by: Cyrill Gorcunov