summaryrefslogtreecommitdiff
AgeCommit message (Collapse)Author
2025-11-27liveupdate: luo_session: add sessions supportPasha Tatashin
Introduce concept of "Live Update Sessions" within the LUO framework. LUO sessions provide a mechanism to group and manage `struct file *` instances (representing file descriptors) that need to be preserved across a kexec-based live update. Each session is identified by a unique name and acts as a container for file objects whose state is critical to a userspace workload, such as a virtual machine or a high-performance database, aiming to maintain their functionality across a kernel transition. This groundwork establishes the framework for preserving file-backed state across kernel updates, with the actual file data preservation mechanisms to be implemented in subsequent patches. [dan.carpenter@linaro.org: fix use after free in luo_session_deserialize()] Link: https://lkml.kernel.org/r/c5dd637d7eed3a3be48c5e9fedb881596a3b1f5a.1764163896.git.dan.carpenter@linaro.org Link: https://lkml.kernel.org/r/20251125165850.3389713-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kexec: call liveupdate_reboot() before kexecPasha Tatashin
Modify the kernel_kexec() to call liveupdate_reboot(). This ensures that the Live Update Orchestrator is notified just before the kernel executes the kexec jump. The liveupdate_reboot() function triggers the final freeze event, allowing participating FDs perform last-minute check or state saving within the blackout window. If liveupdate_reboot() returns an error (indicating a failure during LUO finalization), the kexec operation is aborted to prevent proceeding with an inconsistent state. An error is returned to user. Link: https://lkml.kernel.org/r/20251125165850.3389713-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: luo_core: integrate with KHOPasha Tatashin
Integrate the LUO with the KHO framework to enable passing LUO state across a kexec reboot. This patch implements the lifecycle integration with KHO: 1. Incoming State: During early boot (`early_initcall`), LUO checks if KHO is active. If so, it retrieves the "LUO" subtree, verifies the "luo-v1" compatibility string, and reads the `liveupdate-number` to track the update count. 2. Outgoing State: During late initialization (`late_initcall`), LUO allocates a new FDT for the next kernel, populates it with the basic header (compatible string and incremented update number), and registers it with KHO (`kho_add_subtree`). 3. Finalization: The `liveupdate_reboot()` notifier is updated to invoke `kho_finalize()`. This ensures that all memory segments marked for preservation are properly serialized before the kexec jump. Link: https://lkml.kernel.org/r/20251125165850.3389713-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: luo_core: Live Update OrchestratorPasha Tatashin
Patch series "Live Update Orchestrator", v8. 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. Introduce LUO, a mechanism intended to facilitate kernel updates while keeping designated devices operational across the transition (e.g., via kexec). The primary use case is updating hypervisors with minimal disruption to running virtual machines. For userspace side of hypervisor update we have copyless migration. LUO is for updating the kernel. This initial patch lays the groundwork for the LUO subsystem. Further functionality, including the implementation of state transition logic, integration with KHO, and hooks for subsystems and file descriptors, will be added in subsequent patches. Create a character device at /dev/liveupdate. A new uAPI header, <uapi/linux/liveupdate.h>, will define the necessary structures. The magic number for IOCTL is registered in Documentation/userspace-api/ioctl/ioctl-number.rst. Link: https://lkml.kernel.org/r/20251125165850.3389713-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20251125165850.3389713-2-pasha.tatashin@soleen.com Link: https://lore.kernel.org/all/20251018000713.677779-1-vipinsh@google.com/ [1] Link: https://lore.kernel.org/linux-iommu/20250928190624.3735830-1-skhawaja@google.com [2] Link: https://lore.kernel.org/linux-pci/20250916-luo-pci-v2-0-c494053c3c08@kernel.org [3] Link: https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v8 [4] Link: https://tinyurl.com/luoddesign [5] Link: https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [6] Link: https://lore.kernel.org/all/20251115233409.768044-1-pasha.tatashin@soleen.com [7] Link: https://github.com/soleen/linux/blob/luo/v8b03/diff.v7.v8 [8] Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: add Kconfig option to enable KHO by defaultPasha Tatashin
Currently, Kexec Handover must be explicitly enabled via the kernel command line parameter `kho=on`. For workloads that rely on KHO as a foundational requirement (such as the upcoming Live Update Orchestrator), requiring an explicit boot parameter adds redundant configuration steps. Introduce CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT. When selected, KHO defaults to enabled. This is equivalent to passing kho=on at boot. The behavior can still be disabled at runtime by passing kho=off. Link: https://lkml.kernel.org/r/20251114190002.3311679-14-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: allow memory preservation state updates after finalizationPasha Tatashin
Currently, kho_preserve_* and kho_unpreserve_* return -EBUSY if KHO is finalized. This enforces a rigid "freeze" on the KHO memory state. With the introduction of re-entrant finalization, this restriction is no longer necessary. Users should be allowed to modify the preservation set (e.g., adding new pages or freeing old ones) even after an initial finalization. The intended workflow for updates is now: 1. Modify state (preserve/unpreserve). 2. Call kho_finalize() again to refresh the serialized metadata. Remove the kho_out.finalized checks to enable this dynamic behavior. This also allows to convert kho_unpreserve_* functions to void, as they do not return any error anymore. Link: https://lkml.kernel.org/r/20251114190002.3311679-13-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: allow kexec load before KHO finalizationPasha Tatashin
Currently, kho_fill_kimage() checks kho_out.finalized and returns early if KHO is not yet finalized. This enforces a strict ordering where userspace must finalize KHO *before* loading the kexec image. This is restrictive, as standard workflows often involve loading the target kernel early in the lifecycle and finalizing the state (FDT) only immediately before the reboot. Since the KHO FDT resides at a physical address allocated during boot (kho_init), its location is stable. We can attach this stable address to the kimage regardless of whether the content has been finalized yet. Relax the check to only require kho_enable, allowing kexec_file_load to proceed at any time. Link: https://lkml.kernel.org/r/20251114190002.3311679-12-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: update FDT dynamically for subtree addition/removalPasha Tatashin
Currently, sub-FDTs were tracked in a list (kho_out.sub_fdts) and the final FDT is constructed entirely from scratch during kho_finalize(). We can maintain the FDT dynamically: 1. Initialize a valid, empty FDT in kho_init(). 2. Use fdt_add_subnode and fdt_setprop in kho_add_subtree to update the FDT immediately when a subsystem registers. 3. Use fdt_del_node in kho_remove_subtree to remove entries. This removes the need for the intermediate sub_fdts list and the reconstruction logic in kho_finalize(). kho_finalize() now only needs to trigger memory map serialization. Link: https://lkml.kernel.org/r/20251114190002.3311679-11-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: remove abort functionality and support state refreshPasha Tatashin
Previously, KHO required a dedicated kho_abort() function to clean up state before kho_finalize() could be called again. This was necessary to handle complex unwind paths when using notifiers. With the shift to direct memory preservation, the explicit abort step is no longer strictly necessary. Remove kho_abort() and refactor kho_finalize() to handle re-entry. If kho_finalize() is called while KHO is already finalized, it will now automatically clean up the previous memory map and state before generating a new one. This allows the KHO state to be updated/refreshed simply by triggering finalize again. Update debugfs to return -EINVAL if userspace attempts to write 0 to the finalize attribute, as explicit abort is no longer supported. Link: https://lkml.kernel.org/r/20251114190002.3311679-10-pasha.tatashin@soleen.com Suggested-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: remove global preserved_mem_map and store state in FDTPasha Tatashin
Currently, the serialized memory map is tracked via kho_out.preserved_mem_map and copied to the FDT during finalization. This double tracking is redundant. Remove preserved_mem_map from kho_out. Instead, maintain the physical address of the head chunk directly in the preserved-memory-map FDT property. Introduce kho_update_memory_map() to manage this property. This function handles: 1. Retrieving and freeing any existing serialized map (handling the abort/retry case). 2. Updating the FDT property with the new chunk address. This establishes the FDT as the single source of truth for the handover state. Link: https://lkml.kernel.org/r/20251114190002.3311679-9-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: simplify serialization and remove __kho_abortPasha Tatashin
Currently, __kho_finalize() performs memory serialization in the middle of FDT construction. If FDT construction fails later, the function must manually clean up the serialized memory via __kho_abort(). Refactor __kho_finalize() to perform kho_mem_serialize() only after the FDT has been successfully constructed and finished. This reordering has two benefits: 1. It avoids expensive serialization work if FDT generation fails. 2. It removes the need for cleanup in the FDT error path. As a result, the internal helper __kho_abort() is no longer needed for internal error handling. Inline its remaining logic (cleanup of the preserved memory map) directly into kho_abort() and remove the helper. Link: https://lkml.kernel.org/r/20251114190002.3311679-8-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: always expose output FDT in debugfsPasha Tatashin
Currently, the output FDT is added to debugfs only when KHO is finalized and removed when aborted. There is no need to hide the FDT based on the state. Always expose it starting from initialization. This aids the transition toward removing the explicit abort functionality and converting KHO to be fully stateless. Link: https://lkml.kernel.org/r/20251114190002.3311679-7-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: verify deserialization status and fix FDT alignment accessPasha Tatashin
During boot, kho_restore_folio() relies on the memory map having been successfully deserialized. If deserialization fails or no map is present, attempting to restore the FDT folio is unsafe. Update kho_mem_deserialize() to return a boolean indicating success. Use this return value in kho_memory_init() to disable KHO if deserialization fails. Also, the incoming FDT folio is never used, there is no reason to restore it. Additionally, use get_unaligned() to retrieve the memory map pointer from the FDT. FDT properties are not guaranteed to be naturally aligned, and accessing a 64-bit value via a pointer that is only 32-bit aligned can cause faults. Link: https://lkml.kernel.org/r/20251114190002.3311679-6-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: preserve FDT folio only once during initializationPasha Tatashin
Currently, the FDT folio is preserved inside __kho_finalize(). If the user performs multiple finalize/abort cycles, kho_preserve_folio() is called repeatedly for the same FDT folio. Since the FDT folio is allocated once during kho_init(), it should be marked for preservation at the same time. Move the preservation call to kho_init() to align the preservation state with the object's lifecycle and simplify the finalize path. Also, pre-zero the FDT tree so we do not expose random bits to the user and to the next kernel by using the new kho_alloc_preserve() api. Link: https://lkml.kernel.org/r/20251114190002.3311679-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: introduce high-level memory allocation APIPasha Tatashin
Currently, clients of KHO must manually allocate memory (e.g., via alloc_pages), calculate the page order, and explicitly call kho_preserve_folio(). Similarly, cleanup requires separate calls to unpreserve and free the memory. Introduce a high-level API to streamline this common pattern: - kho_alloc_preserve(size): Allocates physically contiguous, zeroed memory and immediately marks it for preservation. - kho_unpreserve_free(ptr): Unpreserves and frees the memory in the current kernel. - kho_restore_free(ptr): Restores the struct page state of preserved memory in the new kernel and immediately frees it to the page allocator. [pasha.tatashin@soleen.com: build fixes] Link: https://lkml.kernel.org/r/CA+CK2bBgXDhrHwTVgxrw7YTQ-0=LgW0t66CwPCgG=C85ftz4zw@mail.gmail.com Link: https://lkml.kernel.org/r/20251114190002.3311679-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: convert __kho_abort() to return voidPasha Tatashin
The internal helper __kho_abort() always returns 0 and has no failure paths. Its return value is ignored by __kho_finalize and checked needlessly by kho_abort. Change the return type to void to reflect that this function cannot fail, and simplify kho_abort by removing dead error handling code. Link: https://lkml.kernel.org/r/20251114190002.3311679-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: fix misleading log message in kho_populate()Pasha Tatashin
Patch series "kho: simplify state machine and enable dynamic updates", v2. This patch series refactors the Kexec Handover subsystem to transition from a rigid, state-locked model to a dynamic, re-entrant architecture. It also introduces usability improvements. Motivation Currently, KHO relies on a strict state machine where memory preservation is locked upon finalization. If a change is required, the user must explicitly "abort" to reset the state. Additionally, the kexec image cannot be loaded until KHO is finalized, and the FDT is rebuilt from scratch on every finalization. This series simplifies this workflow to support "load early, finalize late" scenarios. Key Changes State Machine Simplification: - Removed kho_abort(). kho_finalize() is now re-entrant; calling it a second time automatically flushes the previous serialized state and generates a fresh one. - Removed kho_out.finalized checks from preservation APIs, allowing drivers to add/remove pages even after an initial finalization. - Decoupled kexec_file_load from KHO finalization. The KHO FDT physical address is now stable from boot, allowing the kexec image to be loaded before the handover metadata is finalized. FDT Management: - The FDT is now updated in-place dynamically when subtrees are added or removed, removing the need for complex reconstruction logic. - The output FDT is always exposed in debugfs (initialized and zeroed at boot), improving visibility and debugging capabilities throughout the system lifecycle. - Removed the redundant global preserved_mem_map pointer, establishing the FDT property as the single source of truth. New Features & API Enhancements: - High-Level Allocators: Introduced kho_alloc_preserve() and friends to reduce boilerplate for drivers that need to allocate, preserve, and eventually restore simple memory buffers. - Configuration: Added CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT to allow KHO to be active by default without requiring the kho=on command line parameter. Fixes: - Fixed potential alignment faults when accessing 64-bit FDT properties. - Fixed the lifecycle of the FDT folio preservation (now preserved once at init). This patch (of 13): The log message in kho_populate() currently states "Will skip init for some devices". This implies that Kexec Handover always involves skipping device initialization. However, KHO is a generic mechanism used to preserve kernel memory across reboot for various purposes, such as memfd, telemetry, or reserve_mem. Skipping device initialization is a specific property of live update drivers using KHO, not a property of the mechanism itself. Remove the misleading suffix to accurately reflect the generic nature of KHO discovery. Link: https://lkml.kernel.org/r/20251114190002.3311679-2-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Coiby Xu <coxu@redhat.com> Cc: Dave Vasilevsky <dave@vasilevsky.ca> Cc: Eric Biggers <ebiggers@google.com> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: kho: use %pe format specifier for error pointer printingZhu Yanjun
Make pr_xxx() call to use the %pe format specifier instead of %d. The %pe specifier prints a symbolic error string (e.g., -ENOMEM, -EINVAL) when given an error pointer created with ERR_PTR(err). This change enhances the clarity and diagnostic value of the error message by showing a descriptive error name rather than a numeric error code. Note, that some err are still printed by value, as those errors might come from libfdt and not regular errnos. Link: https://lkml.kernel.org/r/20251101142325.1326536-10-pasha.tatashin@soleen.com Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev> Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Simon Horman <horms@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27MAINTAINERS: update KHO maintainersPasha Tatashin
Changyuan does not have cycles to commit to the upstream work of KHO. Remove from KHO maintainers. Link: https://lkml.kernel.org/r/20251101142325.1326536-9-pasha.tatashin@soleen.com Signed-off-by: Changyuan Lyu <changyuanl@google.com> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: kho: move to kernel/liveupdatePasha Tatashin
Move KHO to kernel/liveupdate/ in preparation of placing all Live Update core kernel related files to the same place. [pasha.tatashin@soleen.com: disable the menu when DEFERRED_STRUCT_PAGE_INIT] Link: https://lkml.kernel.org/r/CA+CK2bAvh9Oa2SLfsbJ8zztpEjrgr_hr-uGgF1coy8yoibT39A@mail.gmail.com Link: https://lkml.kernel.org/r/20251101142325.1326536-8-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: don't unpreserve memory during abortPasha Tatashin
KHO allows clients to preserve memory regions at any point before the KHO state is finalized. The finalization process itself involves KHO performing its own actions, such as serializing the overall preserved memory map. If this finalization process is aborted, the current implementation destroys KHO's internal memory tracking structures (`kho_out.ser.track.orders`). This behavior effectively unpreserves all memory from KHO's perspective, regardless of whether those preservations were made by clients before the finalization attempt or by KHO itself during finalization. This premature unpreservation is incorrect. An abort of the finalization process should only undo actions taken by KHO as part of that specific finalization attempt. Individual memory regions preserved by clients prior to finalization should remain preserved, as their lifecycle is managed by the clients themselves. These clients might still need to call kho_unpreserve_folio() or kho_unpreserve_phys() based on their own logic, even after a KHO finalization attempt is aborted. Link: https://lkml.kernel.org/r/20251101142325.1326536-7-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27test_kho: unpreserve memory in case of errorPasha Tatashin
If there is an error half way through KHO memory preservation, we should rollback and unpreserve everything that is partially preserved. Link: https://lkml.kernel.org/r/20251101142325.1326536-6-pasha.tatashin@soleen.com Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27memblock: unpreserve memory in case of errorPasha Tatashin
If there is an error half way through KHO memory preservation, we should rollback and unpreserve everything that is partially preserved. [akpm@linux-foundation.org: s/err_no_fdt_page/err_report/ in prepare_kho_fdt(), per Mike] Link: https://lkml.kernel.org/r/20251101142325.1326536-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Suggested-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: add interfaces to unpreserve folios, page ranges, and vmallocPasha Tatashin
Allow users of KHO to cancel the previous preservation by adding the necessary interfaces to unpreserve folio, pages, and vmallocs. Link: https://lkml.kernel.org/r/20251101142325.1326536-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: drop notifiersMike Rapoport (Microsoft)
The KHO framework uses a notifier chain as the mechanism for clients to participate in the finalization process. While this works for a single, central state machine, it is too restrictive for kernel-internal components like pstore/reserve_mem or IMA. These components need a simpler, direct way to register their state for preservation (e.g., during their initcall) without being part of a complex, shutdown-time notifier sequence. The notifier model forces all participants into a single finalization flow and makes direct preservation from an arbitrary context difficult. This patch refactors the client participation model by removing the notifier chain and introducing a direct API for managing FDT subtrees. The core kho_finalize() and kho_abort() state machine remains, but clients now register their data with KHO beforehand. Link: https://lkml.kernel.org/r/20251101142325.1326536-3-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Graf <graf@amazon.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Simon Horman <horms@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27kho: make debugfs interface optionalPasha Tatashin
Patch series "liveupdate: Rework KHO for in-kernel users", v9. This series refactors the KHO framework to better support in-kernel users like the upcoming LUO. The current design, which relies on a notifier chain and debugfs for control, is too restrictive for direct programmatic use. The core of this rework is the removal of the notifier chain in favor of a direct registration API. This decouples clients from the shutdown-time finalization sequence, allowing them to manage their preserved state more flexibly and at any time. In support of this new model, this series also: - Makes the debugfs interface optional. - Introduces APIs to unpreserve memory and fixes a bug in the abort path where client state was being incorrectly discarded. Note that this is an interim step, as a more comprehensive fix is planned as part of the stateless KHO work [1]. - Moves all KHO code into a new kernel/liveupdate/ directory to consolidate live update components. This patch (of 9): Currently, KHO is controlled via debugfs interface, but once LUO is introduced, it can control KHO, and the debug interface becomes optional. Add a separate config CONFIG_KEXEC_HANDOVER_DEBUGFS that enables the debugfs interface, and allows to inspect the tree. Move all debugfs related code to a new file to keep the .c files clear of ifdefs. Link: https://lkml.kernel.org/r/20251101142325.1326536-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20251101142325.1326536-2-pasha.tatashin@soleen.com Link: https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [1] Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Simon Horman <horms@kernel.org> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27selftests: complete kselftest include centralizationBala-Vignesh-Reddy
This follow-up patch completes centralization of kselftest.h and ksefltest_harness.h includes in remaining seltests files, replacing all relative paths with a non-relative paths using shared -I include path in lib.mk Tested with gcc-13.3 and clang-18.1, and cross-compiled successfully on riscv, arm64, x86_64 and powerpc arch. [reddybalavignesh9979@gmail.com: add selftests include path for kselftest.h] Link: https://lkml.kernel.org/r/20251017090201.317521-1-reddybalavignesh9979@gmail.com Link: https://lkml.kernel.org/r/20251016104409.68985-1-reddybalavignesh9979@gmail.com Signed-off-by: Bala-Vignesh-Reddy <reddybalavignesh9979@gmail.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/lkml/20250820143954.33d95635e504e94df01930d0@linux-foundation.org/ Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Günther Noack <gnoack@google.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mickael Salaun <mic@digikod.net> Cc: Ming Lei <ming.lei@redhat.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Simon Horman <horms@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27fork: stop ignoring NUMA while handling cached thread stacksMateusz Guzik
1. the numa parameter was straight up ignored. 2. nothing was done to check if the to-be-cached/allocated stack matches the local node The id remains ignored on free in case of memoryless nodes. Note the current caching is already bad as the cache keeps overflowing and a different solution is needed for the long run, to be worked out(tm). Stats collected over a kernel build with the patch with the following topology: NUMA node(s): 2 NUMA node0 CPU(s): 0-11 NUMA node1 CPU(s): 12-23 caller's node vs stack backing pages on free: matching: 50083 (70%) mismatched: 21492 (30%) caching efficiency: cached: 32651 (65.2%) dropped: 17432 (34.8%) Link: https://lkml.kernel.org/r/20251120054015.3019419-1-mjguzik@gmail.com Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Linus Waleij <linus.walleij@linaro.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Kees Cook <kees@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27rbtree: inline rb_last()Eric Dumazet
This is a very small function, inlining it saves cpu cycles in TCP by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 122 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux After: size vmlinux text data bss dec hex filename 34811659 22177365 5685248 62674272 3bc5560 vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-3-edumazet@google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Neal Cardwell <ncardwell@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Stehen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27rbtree: inline rb_first()Eric Dumazet
Patch series "rbree: inline rb_first() and rb_last()". Inline these two small helpers, heavily used in TCP and FQ packet scheduler, and in many other places. This reduces kernel text size, and brings an 1.5 % improvement on network TCP stress test. This patch (of 2): This is a very small function, inlining it saves cpu cycles by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 744 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34812525 22177365 5685248 62675138 3bc58c2 vmlinux After: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-1-edumazet@google.com Link: https://lkml.kernel.org/r/20251114140646.3817319-2-edumazet@google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Neal Cardwell <ncardwell@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Stehen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27Merge branch 'mm-hotfixes-stable' into mm-nonmm-stable in order to be ableAndrew Morton
to merge "kho: make debugfs interface optional" into mm-nonmm-stable.
2025-11-28drm/i915/panic: Get the crtc from the correct placeVille Syrjälä
Use hw.crtc as opposed to uapi.crtc in the panic code. I suspect this stuff doesn't handle joiner correctly in other ways either but can't be bothered to dig deeper. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patch.msgid.link/20251119181606.17129-6-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
2025-11-28drm/i915: Use hw.active instead of uapi.active in the initial plane readoutVille Syrjälä
We're interested in the actual hardware state rather than the uapi state, so grab the crtc active flag from the correct spot. In practice the two will be identical here becase .get_initial_plane_config() will reject the initial FB when joiner is active. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patch.msgid.link/20251119181606.17129-5-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
2025-11-28drm/i915/psr: Use hw.rotation instead of uapi.rotationVille Syrjälä
Presumably we're tryign to check if the hw plane is actually rotated or not, so grab that information from the correct plane (hw.rotation). Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patch.msgid.link/20251119181606.17129-4-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
2025-11-28drm/i915/psr: Use hw.crtc instead of uapi.crtcVille Syrjälä
uapi.crtc is not set for joiner secondary pipes, so generally should not be used anywhere after the initial state copy. Switch to hw.crtc which actually indicates that the plane is enabled. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patch.msgid.link/20251119181606.17129-3-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
2025-11-27Merge tag 'riscv-config-for-v6.19' of ↵Arnd Bergmann
https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux into soc/defconfig RISC-V config for v6.19 Spacemit: The Spacemit k1 wants the freescale qspi driver enabled as a module as they appear to be rather similar IPs. Signed-off-by: Conor Dooley <conor.dooley@microchip.com> * tag 'riscv-config-for-v6.19' of https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux: riscv: defconfig: enable SPI_FSL_QUADSPI as a module Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-28drm/i915: Use the proper (hw.crtc) for the cursor unpin vblank workerVille Syrjälä
uapi.crtc is NULL for joiner secondary pipes, so using that is nonsense in most places. Switch to hw.crtc so that we use the deferred cursor unpin also on joiner secondary pipes. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patch.msgid.link/20251119181606.17129-2-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>
2025-11-27Merge tag 'cache-for-v6.19' of ↵Arnd Bergmann
https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux into soc/drivers-late standalone cache drivers for v6.19 ccache: Add a compatible for the pic64gx SoC. No driver change needed, as it falls back to the PolarFire SoC. hisi hha/generic cpu cache maintenance: Add support for a non-architectural mechanism for invalidating memory regions, needed for some cxl implementations on arm64 (and probably elsewhere in the future). The HiSilicon Hydra Home Agent is the first driver to provide this support. Signed-off-by: Conor Dooley <conor.dooley@microchip.com> * tag 'cache-for-v6.19' of https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux: MAINTAINERS: refer to intended file in STANDALONE CACHE CONTROLLER DRIVERS cache: Support cache maintenance for HiSilicon SoC Hydra Home Agent cache: Make top level Kconfig menu a boolean dependent on RISCV MAINTAINERS: Add Jonathan Cameron to drivers/cache and add lib/cache_maint.c + header arm64: Select GENERIC_CPU_CACHE_MAINTENANCE lib: Support ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION memregion: Support fine grained invalidate by cpu_cache_invalidate_memregion() memregion: Drop unused IORES_DESC_* parameter from cpu_cache_invalidate_memregion() dt-bindings: cache: sifive,ccache0: add a pic64gx compatible Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27Merge tag 'soc-drivers-for-v6.19' of ↵Arnd Bergmann
https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux into soc/drivers-late RISC-V soc-drivers for v6.19 Microchip: Add bindings and mfd drivers for two syscon regions on PolarFire SoC, needed as part of a rework of the devicetree to permit supporting, among other things, pinctrl sanely and avoiding the "new" pic64gx SoC ever using the original incorrect clock nodes. Fiddle with the Microchip RISC-V MAINTAINERS entry to add these drivers and avoid branding it FPGA only. Signed-off-by: Conor Dooley <conor.dooley@microchip.com> * tag 'soc-drivers-for-v6.19' of https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux: MAINTAINERS: rename Microchip RISC-V entry MAINTAINERS: add new soc drivers to Microchip RISC-V entry soc: microchip: add mfd drivers for two syscon regions on PolarFire SoC dt-bindings: soc: microchip: document the simple-mfd syscon on PolarFire SoC Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27Merge tag 'apple-soc-drivers-6.19' of ↵Arnd Bergmann
https://git.kernel.org/pub/scm/linux/kernel/git/sven/linux into soc/drivers-late Apple SoC driver updates for 6.18 Two small fixes: - mailbox: Stop leaking a reference to the mbox platform device during lookup - sart: drop device reference after lookup since it's no longer used afterwards Signed-off-by: Sven Peter <sven@kernel.org> * tag 'apple-soc-drivers-6.19' of https://git.kernel.org/pub/scm/linux/kernel/git/sven/linux: soc: apple: sart: drop device reference after lookup soc: apple: mailbox: fix device leak on lookup Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27Merge tag 'soc_fsl-6.19-1' of ↵Arnd Bergmann
git://git.kernel.org/pub/scm/linux/kernel/git/chleroy/linux into soc/drivers-late FSL SOC Changes for 6.19 - A couple misc changes to fsl/qbman - Update email address for Christophe Leroy in MAINTAINERS * tag 'soc_fsl-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chleroy/linux: soc: fsl: qbman: use kmalloc_array() instead of kmalloc() soc: fsl: qbman: add WQ_PERCPU to alloc_workqueue users MAINTAINERS: Update email address for Christophe Leroy Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27Merge tag 'amlogic-drivers-for-v6.19' of ↵Arnd Bergmann
https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux into soc/drivers-late Amlogic Drivers for v6.19: - Canvas device leak fix and error handling simplification - Add more SoCs definitions - Suport more SoCs for meson-gx-ao-secure * tag 'amlogic-drivers-for-v6.19' of https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux: soc: amlogic: meson-gx-socinfo: add new SoCs id dt-bindings: arm: amlogic: meson-gx-ao-secure: support more SoCs soc: amlogic: canvas: simplify lookup error handling soc: amlogic: canvas: fix device leak on lookup Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27keys: Fix grammar and formatting in 'struct key_type' commentsThorsten Blum
s/it/if/ and s/revokation/revocation/, capitalize "clear", and add a period after the sentence. Fix the comment formatting. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2025-11-27Merge tag 'reset-gpio-for-v6.19-2' of ↵Arnd Bergmann
https://git.pengutronix.de/git/pza/linux into soc/drivers-late Reset/GPIO/swnode changes for v6.19 (v2) * Fix chtwc_int33fe build issue since commit d7cdbbc93c56 ("software node: allow referencing firmware nodes"). * tag 'reset-gpio-for-v6.19-2' of https://git.pengutronix.de/git/pza/linux: platform/x86: intel: chtwc_int33fe: don't dereference swnode args Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27Merge tag 'reset-gpio-for-v6.19' of https://git.pengutronix.de/git/pza/linux ↵Arnd Bergmann
into soc/drivers-late Reset/GPIO/swnode changes for v6.19 * Extend software node implementation, allowing its properties to reference existing firmware nodes. * Update the GPIO property interface to use reworked swnode macros. * Rework reset-gpio code to use GPIO lookup via swnode. * Fix spi-cs42l43 driver to work with swnode changes. * tag 'reset-gpio-for-v6.19' of https://git.pengutronix.de/git/pza/linux: reset: gpio: use software nodes to setup the GPIO lookup reset: gpio: convert the driver to using the auxiliary bus reset: make the provider of reset-gpios the parent of the reset device reset: order includes alphabetically in reset/core.c gpio: swnode: allow referencing GPIO chips by firmware nodes spi: cs42l43: Use actual ACPI firmware node for chip selects software node: allow referencing firmware nodes software node: increase the reference of the swnode by its fwnode software node: read the reference args via the fwnode API Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-11-27spi: microchip-core: Code improvementsMark Brown
Merge series from Andy Shevchenko <andriy.shevchenko@linux.intel.com>: While reading some other stuff, I noticed that this driver may be improved. Here is the set of refactoring and cleaning it up.
2025-11-27ASoC: Intel: catpt: Round of fixes and PM changesMark Brown
Merge series from Cezary Rojewski <cezary.rojewski@intel.com>: Set of changes addressing gaps in DRAM offset checks, error paths and PM. The first three patches are straight-forward, the last three relate to the power management. The standing out PM change is removal of the catpt-driver as a system-suspend (S3) blocker. This is a suggestion from Andy as indeed, audio is not a critical component that should prevent the system from going into S3. Whatever happens, the driver can recover on a follow up resume (S3 -> S0).
2025-11-27Add support for cs42l45 into the Intel machine driverMark Brown
Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>: Now that the full class driver is in place we can add support to the Intel machine driver for Cirrus's new SDCA audio CODEC the cs42l45. This makes some minor tweaks to the machine driver itself to support SDCA devices, and then adds the necessary tables etc. to define the device. Note, this series shouldn't have any dependencies on the other series of improvements to the class driver that is already on the list. So either can be merged first.
2025-11-27keys: Replace deprecated strncpy in ecryptfs_fill_auth_tokThorsten Blum
strncpy() is deprecated for NUL-terminated destination buffers; use strscpy_pad() instead to retain the NUL-padding behavior of strncpy(). The destination buffer is initialized using kzalloc() with a 'signature' size of ECRYPTFS_PASSWORD_SIG_SIZE + 1. strncpy() then copies up to ECRYPTFS_PASSWORD_SIG_SIZE bytes from 'key_desc', NUL-padding any remaining bytes if needed, but expects the last byte to be zero. strscpy_pad() also copies the source string to 'signature', and NUL-pads the destination buffer if needed, but ensures it's always NUL-terminated without relying on it being zero-initialized. strscpy_pad() automatically determines the size of the fixed-length destination buffer via sizeof() when the optional size argument is omitted, making an explicit size unnecessary. In encrypted_init(), the source string 'key_desc' is validated by valid_ecryptfs_desc() before calling ecryptfs_fill_auth_tok(), and is therefore NUL-terminated and satisfies the __must_be_cstr() requirement of strscpy_pad(). Link: https://github.com/KSPP/linux/issues/90 Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2025-11-27keys: Remove redundant less-than-zero checksThorsten Blum
The local variables 'size_t datalen' are unsigned and cannot be less than zero. Remove the redundant conditions. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>