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AJvYcCUy4dDd7DeA1y5GGZpHF+B9IMXtxWqzZq84L6uvfBi1ZemngsoFTePRz3QFnl9yyY8FIX+1DXtkcQ==@kvack.org X-Gm-Message-State: AOJu0Yycvjnb0qZYM6c+clDxnV+mH1NU8+lKbJsrI072yKHWT3j7XV4K rOauFweZBXs9aGOLTeJWKYvkGbivwlavT3k9OnmpzKL4TM5YIlukoOwDwrqrf9PRqo8ZrTfvj84 E89DqrQ== X-Received: from japv18.prod.google.com ([2002:a02:cbb2:0:b0:5ce:5b3c:f8c3]) (user=avagin job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6820:6ae6:b0:663:8c6:97a1 with SMTP id 006d021491bc7-66d0c85409bmr5061261eaf.61.1770663974501; Mon, 09 Feb 2026 11:06:14 -0800 (PST) Date: Mon, 9 Feb 2026 19:06:01 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.239.g8d8fc8a987-goog Message-ID: <20260209190605.1564597-1-avagin@google.com> Subject: [PATCH 0/4 v3] 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-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 9CAF2100008 X-Stat-Signature: zx17tzkbxm8w83b19egehetyw1y56pij X-Rspam-User: X-HE-Tag: 1770663975-289897 X-HE-Meta: U2FsdGVkX1/Z8zCH2d0n4TLG4VWpJGjYTK6dtWEM5sa8BZhRTxOrxfvWTHzi8ugJEF9wvqFG/43FFmo/X2EOVvNOrTDU9nBsBuMI3A5mH4BvKoxI9ktRP5xi7wU6UJCe48ykXLf/vElI8y712UXxh3frIIvs62k/A29SiKjJv8zLqnwQ2ZUdTlSvZp8IY28dikWUcOxuBgXd5NoL0xgNESIczhce/JOFrE2hAZlBIj8N/RCed33H0M8wcSVLvQI6+nvQYIdbJJrlqWuUE/aruthMrmB9BGJtsGWl597gOSAhMr6OxzwWGBM3UIcOEYPclGujKjigxPp8Duq78UVRCRAJHk4RxiNp9l1NaCS9AH8yeFXF0MnOwGdj04CKQSJTzYgdKiaHt6CpBd20nUWbTiBHkpMc0CJo3TZqRNJ1jDLbau1/XQ9wtTxLAVtUKdXy5AR2Ivg2Lf06MzVVG3AQwgm+HY40ptZFMob54iEwEWbAukvSDVbXM911aaq9jrbdt0A6hK8ONl0Htlr4rvC+EyXQ/vQWp5g1X3m057rlslU7ALZTJPV59975GER2msVWybeBml2nm8ch3xkyzXp5y3/9937fdtOUykFNdCdNl+eQuRvQBCw9wfqFo591sF6hnkJU4YUNP3yWmsGOEPsz81AxzXHAuG7py7mVoPyZutN/sNpEelVZtkeiCiGWHv+HCggUhDWMwE5idQF2H8A4XLXyR24ZNyzWOOpPhyA/ZMd0ZBsvFrmabG4Suwfeje+07S5zOdQsiEt3ssgCI3MYbLQBFg2SK92AImtE9Plizt8UCoQxjYkKkSldJfxfUKn7L/n0ix2ArLS+LfLqKw8GkNvZro+4Imm3lc2++VO5CKKWhehys/9UvgEYLKf7iE1i3IFEhOS3ped/J+rBGyx3/IJm6jHQSpWBcZpxpoTNEU0+cMxUuYAt2QrU4/7USNe/NotPVvRZjWrXz8I+Osh D9LspPnu 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 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(). 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 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