| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251115233409.768044-1-pasha.tatashin@soleen.com> Date: Sat, 15 Nov 2025 18:33:46 -0500 From: Pasha Tatashin <pasha.tatashin@...een.com> To: pratyush@...nel.org, jasonmiu@...gle.com, graf@...zon.com, pasha.tatashin@...een.com, rppt@...nel.org, dmatlack@...gle.com, rientjes@...gle.com, corbet@....net, rdunlap@...radead.org, ilpo.jarvinen@...ux.intel.com, kanie@...ux.alibaba.com, ojeda@...nel.org, aliceryhl@...gle.com, masahiroy@...nel.org, akpm@...ux-foundation.org, tj@...nel.org, yoann.congal@...le.fr, mmaurer@...gle.com, roman.gushchin@...ux.dev, chenridong@...wei.com, axboe@...nel.dk, mark.rutland@....com, jannh@...gle.com, vincent.guittot@...aro.org, hannes@...xchg.org, dan.j.williams@...el.com, david@...hat.com, joel.granados@...nel.org, rostedt@...dmis.org, anna.schumaker@...cle.com, song@...nel.org, linux@...ssschuh.net, linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, linux-mm@...ck.org, gregkh@...uxfoundation.org, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com, rafael@...nel.org, dakr@...nel.org, bartosz.golaszewski@...aro.org, cw00.choi@...sung.com, myungjoo.ham@...sung.com, yesanishhere@...il.com, Jonathan.Cameron@...wei.com, quic_zijuhu@...cinc.com, aleksander.lobakin@...el.com, ira.weiny@...el.com, andriy.shevchenko@...ux.intel.com, leon@...nel.org, lukas@...ner.de, bhelgaas@...gle.com, wagi@...nel.org, djeffery@...hat.com, stuart.w.hayes@...il.com, ptyadav@...zon.de, lennart@...ttering.net, brauner@...nel.org, linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org, saeedm@...dia.com, ajayachandra@...dia.com, jgg@...dia.com, parav@...dia.com, leonro@...dia.com, witu@...dia.com, hughd@...gle.com, skhawaja@...gle.com, chrisl@...nel.org Subject: [PATCH v6 00/20] Live Update Orchestrator This series introduces the Live Update Orchestrator, a kernel subsystem designed to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisors to be updated with minimal downtime for running virtual machines. LUO achieves this by preserving the state of selected resources, such as memory, devices and their dependencies, across the kernel transition. As a key feature, this series includes support for preserving memfd file descriptors, which allows critical in-memory data, such as guest RAM or any other large memory region, to be maintained in RAM across the kexec reboot. The other series that use LUO, are VFIO [1], IOMMU [2], and PCI [3] preservations. Github repo of this series [4]. The core of LUO is a framework for managing the lifecycle of preserved resources through a userspace-driven interface. Key features include: - Session Management Userspace agent (i.e. luod [5]) creates named sessions, each represented by a file descriptor (via centralized agent that controls /dev/liveupdate). The lifecycle of all preserved resources within a session is tied to this FD, ensuring automatic kernel cleanup if the controlling userspace agent crashes or exits unexpectedly. - File Preservation A handler-based framework allows specific file types (demonstrated here with memfd) to be preserved. Handlers manage the serialization, restoration, and lifecycle of their specific file types. - File-Lifecycle-Bound State A new mechanism for managing shared global state whose lifecycle is tied to the preservation of one or more files. This is crucial for subsystems like IOMMU or HugeTLB, where multiple file descriptors may depend on a single, shared underlying resource that must be preserved only once. - KHO Integration LUO drives the Kexec Handover framework programmatically to pass its serialized metadata to the next kernel. The LUO state is finalized and added to the kexec image just before the reboot is triggered. In the future this step will also be removed once stateless KHO is merged [6]. - Userspace Interface Control is provided via ioctl commands on /dev/liveupdate for creating and retrieving sessions, as well as on session file descriptors for managing individual files. - Testing The series includes a set of selftests, including userspace API validation, kexec-based lifecycle tests for various session and file scenarios, and a new in-kernel test module to validate the FLB logic. Changelog since v5 [7] - Moved internal luo_alloc/free_* memory helpers to generic kho_alloc/free_* APIs, and submitted as a separate KHO series [8]. - Moved the liveupdate_reboot() invocation from kernel/reboot.c to kernel_kexec() in kernel/kexec_core.c. - Moved generic KHO enabling patches (debugfs, kimage logic) out of this series and into the base KHO series. - Feedback: Addressed review comments from Mike Rapoport and Pratyush Yadav. [1] https://lore.kernel.org/all/20251018000713.677779-1-vipinsh@google.com/ [2] https://lore.kernel.org/linux-iommu/20250928190624.3735830-1-skhawaja@google.com [3] https://lore.kernel.org/linux-pci/20250916-luo-pci-v2-0-c494053c3c08@kernel.org [4] https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v6 [5] https://tinyurl.com/luoddesign [6] https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [7] https://lore.kernel.org/all/20251107210526.257742-1-pasha.tatashin@soleen.com [8] https://lore.kernel.org/all/20251114190002.3311679-1-pasha.tatashin@soleen.com Pasha Tatashin (14): liveupdate: luo_core: luo_ioctl: Live Update Orchestrator liveupdate: luo_core: integrate with KHO kexec: call liveupdate_reboot() before kexec liveupdate: luo_session: add sessions support liveupdate: luo_ioctl: add user interface liveupdate: luo_file: implement file systems callbacks liveupdate: luo_session: Add ioctls for file preservation liveupdate: luo_flb: Introduce File-Lifecycle-Bound global state docs: add luo documentation MAINTAINERS: add liveupdate entry selftests/liveupdate: Add userspace API selftests selftests/liveupdate: Add kexec-based selftest for session lifecycle selftests/liveupdate: Add kexec test for multiple and empty sessions tests/liveupdate: Add in-kernel liveupdate test Pratyush Yadav (6): mm: shmem: use SHMEM_F_* flags instead of VM_* flags mm: shmem: allow freezing inode mapping mm: shmem: export some functions to internal.h liveupdate: luo_file: add private argument to store runtime state mm: memfd_luo: allow preserving memfd docs: add documentation for memfd preservation via LUO Documentation/core-api/index.rst | 1 + Documentation/core-api/liveupdate.rst | 71 ++ Documentation/mm/index.rst | 1 + Documentation/mm/memfd_preservation.rst | 23 + Documentation/userspace-api/index.rst | 1 + .../userspace-api/ioctl/ioctl-number.rst | 2 + Documentation/userspace-api/liveupdate.rst | 20 + MAINTAINERS | 15 + include/linux/liveupdate.h | 265 +++++ include/linux/liveupdate/abi/luo.h | 238 +++++ include/linux/liveupdate/abi/memfd.h | 88 ++ include/linux/shmem_fs.h | 23 + include/uapi/linux/liveupdate.h | 216 +++++ kernel/kexec_core.c | 5 + kernel/liveupdate/Kconfig | 27 + kernel/liveupdate/Makefile | 9 + kernel/liveupdate/luo_core.c | 252 +++++ kernel/liveupdate/luo_file.c | 906 ++++++++++++++++++ kernel/liveupdate/luo_flb.c | 658 +++++++++++++ kernel/liveupdate/luo_internal.h | 95 ++ kernel/liveupdate/luo_ioctl.c | 223 +++++ kernel/liveupdate/luo_session.c | 600 ++++++++++++ lib/Kconfig.debug | 23 + lib/tests/Makefile | 1 + lib/tests/liveupdate.c | 143 +++ mm/Makefile | 1 + mm/internal.h | 6 + mm/memfd_luo.c | 671 +++++++++++++ mm/shmem.c | 50 +- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/liveupdate/.gitignore | 3 + tools/testing/selftests/liveupdate/Makefile | 40 + tools/testing/selftests/liveupdate/config | 5 + .../testing/selftests/liveupdate/do_kexec.sh | 16 + .../testing/selftests/liveupdate/liveupdate.c | 348 +++++++ .../selftests/liveupdate/luo_kexec_simple.c | 114 +++ .../selftests/liveupdate/luo_multi_session.c | 190 ++++ .../selftests/liveupdate/luo_test_utils.c | 168 ++++ .../selftests/liveupdate/luo_test_utils.h | 39 + 39 files changed, 5539 insertions(+), 19 deletions(-) create mode 100644 Documentation/core-api/liveupdate.rst create mode 100644 Documentation/mm/memfd_preservation.rst create mode 100644 Documentation/userspace-api/liveupdate.rst create mode 100644 include/linux/liveupdate.h create mode 100644 include/linux/liveupdate/abi/luo.h create mode 100644 include/linux/liveupdate/abi/memfd.h create mode 100644 include/uapi/linux/liveupdate.h create mode 100644 kernel/liveupdate/luo_core.c create mode 100644 kernel/liveupdate/luo_file.c create mode 100644 kernel/liveupdate/luo_flb.c create mode 100644 kernel/liveupdate/luo_internal.h create mode 100644 kernel/liveupdate/luo_ioctl.c create mode 100644 kernel/liveupdate/luo_session.c create mode 100644 lib/tests/liveupdate.c create mode 100644 mm/memfd_luo.c create mode 100644 tools/testing/selftests/liveupdate/.gitignore create mode 100644 tools/testing/selftests/liveupdate/Makefile create mode 100644 tools/testing/selftests/liveupdate/config create mode 100755 tools/testing/selftests/liveupdate/do_kexec.sh create mode 100644 tools/testing/selftests/liveupdate/liveupdate.c create mode 100644 tools/testing/selftests/liveupdate/luo_kexec_simple.c create mode 100644 tools/testing/selftests/liveupdate/luo_multi_session.c create mode 100644 tools/testing/selftests/liveupdate/luo_test_utils.c create mode 100644 tools/testing/selftests/liveupdate/luo_test_utils.h -- 2.52.0.rc1.455.g30608eb744-goog
Powered by blists - more mailing lists