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AJvYcCVU03zkZUI3G4nmCMHV1zdFQrW/J1l4RP7Dw7hEbNyOsCaE12/8WOWRJkddRiTtCChu2w5yoE+vng==@kvack.org X-Gm-Message-State: AOJu0YyYBW/3N8z5kzKXoABEwboODV/jtRzAfklP0RKsotoIINA2MXYN 7qL71GSqmYpO8YjotlNewubUXp44vFOTluBM6CO04v0RniVaBIpcPrCS8SxJyWI4U7r6QJrMH32 OK81ngw== X-Received: from jabjy12.prod.google.com ([2002:a05:6638:a30c:b0:5d4:6f13:358c]) (user=avagin job=prod-delivery.src-stubby-dispatcher) by 2002:a4a:e904:0:b0:67b:d1cc:db3b with SMTP id 006d021491bc7-67c22bb5ed4mr10163213eaf.15.1774288441712; Mon, 23 Mar 2026 10:54:01 -0700 (PDT) Date: Mon, 23 Mar 2026 17:53:36 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.983.g0bb29b3bc5-goog Message-ID: <20260323175340.3361311-1-avagin@google.com> Subject: [PATCH 0/4 v5] exec: inherit HWCAPs from the parent process From: Andrei Vagin To: Kees Cook , Andrew Morton Cc: Marek Szyprowski , Cyrill Gorcunov , Mike Rapoport , Alexander Mikhalitsyn , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, criu@lists.linux.dev, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Chen Ridong , Christian Brauner , David Hildenbrand , Eric Biederman , Lorenzo Stoakes , Michal Koutny Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 0CE931C0003 X-Stat-Signature: hanm4mf1ytgmhhct3ek857oj4w3ew85s X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1774288442-438925 X-HE-Meta: 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 OfICM26W 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 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(). v5: - Fix reading of HWCAPs from auxiliary vectors of compat processes. - Defer HWCAP masking until ELF table creation (create_elf_tables) to handle compat process correctly. - arm64: Disable HWCAP inheritance on architecture switch (e.g., AArch64 to AArch32) by clearing MMF_USER_HWCAP, as HWCAP bits have completely different meanings across these architectures. 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 v4: https://lkml.org/lkml/2026/2/17/963 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 (4): exec: inherit HWCAPs from the parent process arm64: elf: clear MMF_USER_HWCAP on architecture switch mm: synchronize saved_auxv access with arg_lock selftests/exec: add test for HWCAP inheritance arch/arm64/include/asm/elf.h | 12 ++- fs/binfmt_elf.c | 13 ++- fs/binfmt_elf_fdpic.c | 13 ++- fs/exec.c | 54 ++++++++++ fs/proc/base.c | 12 ++- include/linux/binfmts.h | 11 ++ include/linux/mm_types.h | 3 +- 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 | 105 +++++++++++++++++++ 12 files changed, 234 insertions(+), 29 deletions(-) create mode 100644 tools/testing/selftests/exec/hwcap_inherit.c -- 2.53.0.959.g497ff81fa9-goog