linux-rng/kernel/Makefile, branch master

Merge tag 'kbuild-7.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

2026-10-21T20:45:44Z

Pull Kbuild / Kconfig updates from Nathan Chancellor: "Kbuild: - Suppress compiler flags in debug info for external module builds - Use '-fmacro-prefix-map' in more places in the build - Merge initial set of changes from Lorenzo's speed up series, along with some fixes found through testing: - Avoid allocating .modinfo in vmlinux - Speed up kallsyms by indexing symbols by token and outputting binary data to disk directly then including in assembly via .incbin - Don't sort $(NM) output when unnecessary - Only emit relocations on the final vmlinx link - Reimplement mksysmap in C - Move many cc-option and ld-option calls into the Kconfig stage to cache their results - Use pigz for gzip compression when available - Move gen_init_cpio and gen_initramfs.sh from usr/ to scripts/ - Add a TOML configuration to scripts/container and update documentation accordingly - Add a generic, opt-in mechanism for checking that headers can compile standalone - Update machine function splitting argument for LLVM 24 rename in AutoFDO build - Miscellaneous minor clean ups, fixes, and hardening, mostly found/fixed via LLMs Kconfig: - Turn recursive ranges into an error - Fix savedefconfig for defaults that were adjusted for being out of range and revert a previously applied workaround - Improvements and hardening around integer and hexadecimal values - Emit a warning when selecting or implying a choice symbol, which has no effect - Emit a warning when KCONFIG_PROBABILITY is malformed - Introduce def_string / def_int / def_hex to mirror the existing def_bool / def_tristate to succinctly set a value and type at the same time. - Add cc-option-str and ld-option-str macros to act like Kbuild's cc-option and ld-option, returning the string when the option is supported, allowing many checks to be moved into Kconfig - Minor usability improvements to Kconfig tests" * tag 'kbuild-7.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (59 commits) kbuild: AutoFDO: Update split machine function argument for upstream rename kbuild: Mark the initcall ordering recipe as recursive kbuild: Mark the gzip recipes as recursive localmodconfig: Explicitly report boolean configs during integrity check scripts/make_fit: Ignore schema checks when decomposing DTBs clang-tools: Import os for broken pipe handling kconfig: use the value argument in sym_get_near_range_bound() kconfig: fix infinite loop in conf_choice() when no choice value is visible kconfig: cleanup stale comment about 'keys' array kconfig: Improve ergonomics around disabling warnings with cc-option scripts/Kconfig.toolchain: Drop compiler symbols from dependencies checkkconfigsymbols.py: Parse Git status output line by line gen_init_cpio: stop parsing on lines with a missing argument list .gitignore: drop Module.markers .gitignore: ignore pacman package signatures kbuild: add header check facility as a manually run static analyzer Documentation: dev-tools: refer to user ID rather than id Documentation: dev-tools: update container.rst with config file scripts: add TOML config to container tool kconfig: tests: {old,save}defconfig: Forward dynamic keyword arguments ...

kbuild: compress the kernel with pigz if available

2026-09-25T23:16:36Z

The gzip step of a kernel build is very lengthy, especially for larger builds such as allmodconfig. gzip itself cannot be run in parallel, however an alternative tool exists that can, providing the same feature set as gzip itself - pigz - which works as a drop-in replacement. On a 128-core Threadripper, gzip -9 of a 36 MiB x86-64 vmlinux.bin takes 1.6s, and with pigz it takes 0.09s, so the performance increase is significant. Therefore introduce the KPGZIP build variable which specifies the compressor to use for the kernel image and default it to pigz if available, or KGZIP otherwise (which itself defaults to gzip). Modules, packaging and the embedded kernel configuration (CONFIG_IKCONFIG) continue to use KGZIP which defaults to a single-threaded gzip instance. Module compression is run in parallel by make, so pigz offers no benefit there, packaging sits outside the build and the embedded configuration is too small to matter. pigz is executed using scripts/jobserver-exec, which reserves the job slots make has free - necessary, as otherwise pigz would just grab unbounded CPUs. The kernel image compression step is always performed at the end of the build so should typically have all job slots available. pigz always provides byte-for-byte identical output across runs regardless of thread count, but pigz and gzip are not guaranteed to generate the same binary output, so reproducible builds must use the same tools consistently. Also update Documentation/kbuild/kbuild.rst to describe KPGZIP and Documentation/process/changes.rst to list the optional pigz dependency. While there, add entries for the other compressor programs. Finally, update scripts/ver_linux to include the pigz version there. Every x86 build ends with the compression of vmlinux.bin, 36MB for defconfig and over 200MB for allmodconfig, no-op builds are unchanged. Whole build, 128-thread Threadripper 9980X, best of N runs: before after delta ------------------------------- x86 defconfig, touch mm/vma.c, gcc 7.7s 6.0s -1.7s (-22%) x86 defconfig, touch mm/vma.c, clang 6.9s 5.4s -1.5s (-21%) x86 defconfig, clean, gcc 28.2s 26.3s -1.8s (-6%) x86 defconfig, clean, clang 28.7s 27.2s -1.5s (-5%) x86 allmodconfig, touch mm/vma.c, gcc 23.7s 15.4s -8.3s (-35%) x86 allmodconfig, touch mm/vma.c, clang 22.5s 15.6s -7.0s (-31%) x86 allmodconfig, clean, gcc 294.1s 278.6s -15.5s (-5%) x86 allmodconfig, clean, clang 283.9s 266.8s -17.1s (-6%) Suggested-by: Kees Cook Link: https://zlib.net/pigz/ Assisted-by: LLM Reviewed-by: Manuel Ebner Reviewed-by: Kees Cook Signed-off-by: Lorenzo Stoakes (ARM) Link: https://patch.msgid.link/20260923-build-speedup-v4-22-73128809a4a4@kernel.org Signed-off-by: Nathan Chancellor

userns: Add KUnit test suite for uid_gid_map

2026-09-09T07:45:01Z

Add a KUnit test suite to verify the insertion and sorting of mappings in struct uid_gid_map. This test suite validates both base extent insertion (<= 5 mappings) and extended extent insertion (> 5 mappings, which triggers the allocation of the forward and reverse pointers). This is especially useful for verifying that the __counted_by_ptr attribute added to 'forward' and 'reverse' pointers works correctly without causing any runtime bounds-checking panics or traps. Signed-off-by: Bill Wendling Link: https://patch.msgid.link/20260908222734.3048684-2-morbo@google.com Tested-by: Bradley Morgan Reviewed-by: Bradley Morgan Signed-off-by: Christian Brauner (Amutable)

exec: introduce struct task_exec_state

2026-05-26T09:02:01Z

Introduce struct task_exec_state, a per-task RCU-protected structure that holds the dumpable mode and the user namespace and stays attached to the task for its full lifetime. task_exec_state_rcu() is the canonical reader: asserts RCU or task_lock is held, WARNs on a NULL state, returns the rcu_dereference()'d pointer. Reviewed-by: Jann Horn Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-2-69f895bc1385@kernel.org Signed-off-by: Christian Brauner (Amutable)

kcov: Enable context analysis

2026-01-05T15:43:34Z

Enable context analysis for the KCOV subsystem. Signed-off-by: Marco Elver Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251219154418.3592607-30-elver@google.com

liveupdate: kho: move to kernel/liveupdate

2025-11-27T22:24:33Z

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 Reviewed-by: Jason Gunthorpe Reviewed-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Changyuan Lyu Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Simon Horman Cc: Tejun Heo Cc: Zhu Yanjun Signed-off-by: Andrew Morton

kho: make debugfs interface optional

2025-11-27T22:24:31Z

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) Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav Cc: Alexander Graf Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Randy Dunlap Cc: Tejun Heo Cc: Changyuan Lyu Cc: Jason Gunthorpe Cc: Simon Horman Cc: Zhu Yanjun Signed-off-by: Andrew Morton

kho: warn and fail on metadata or preserved memory in scratch area

2025-11-10T05:19:41Z

Patch series "KHO: kfence + KHO memory corruption fix", v3. This series fixes a memory corruption bug in KHO that occurs when KFENCE is enabled. The root cause is that KHO metadata, allocated via kzalloc(), can be randomly serviced by kfence_alloc(). When a kernel boots via KHO, the early memblock allocator is restricted to a "scratch area". This forces the KFENCE pool to be allocated within this scratch area, creating a conflict. If KHO metadata is subsequently placed in this pool, it gets corrupted during the next kexec operation. Google is using KHO and have had obscure crashes due to this memory corruption, with stacks all over the place. I would prefer this fix to be properly backported to stable so we can also automatically consume it once we switch to the upstream KHO. Patch 1/3 introduces a debug-only feature (CONFIG_KEXEC_HANDOVER_DEBUG) that adds checks to detect and fail any operation that attempts to place KHO metadata or preserved memory within the scratch area. This serves as a validation and diagnostic tool to confirm the problem without affecting production builds. Patch 2/3 Increases bitmap to PAGE_SIZE, so buddy allocator can be used. Patch 3/3 Provides the fix by modifying KHO to allocate its metadata directly from the buddy allocator instead of slab. This bypasses the KFENCE interception entirely. This patch (of 3): It is invalid for KHO metadata or preserved memory regions to be located within the KHO scratch area, as this area is overwritten when the next kernel is loaded, and used early in boot by the next kernel. This can lead to memory corruption. Add checks to kho_preserve_* and KHO's internal metadata allocators (xa_load_or_alloc, new_chunk) to verify that the physical address of the memory does not overlap with any defined scratch region. If an overlap is detected, the operation will fail and a WARN_ON is triggered. To avoid performance overhead in production kernels, these checks are enabled only when CONFIG_KEXEC_HANDOVER_DEBUG is selected. [rppt@kernel.org: fix KEXEC_HANDOVER_DEBUG Kconfig dependency] Link: https://lkml.kernel.org/r/aQHUyyFtiNZhx8jo@kernel.org [pasha.tatashin@soleen.com: build fix] Link: https://lkml.kernel.org/r/CA+CK2bBnorfsTymKtv4rKvqGBHs=y=MjEMMRg_tE-RME6n-zUw@mail.gmail.com Link: https://lkml.kernel.org/r/20251021000852.2924827-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20251021000852.2924827-2-pasha.tatashin@soleen.com Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Pasha Tatashin Signed-off-by: Mike Rapoport Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Cc: Alexander Graf Cc: Christian Brauner Cc: David Matlack Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Randy Dunlap Cc: Samiullah Khawaja Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-10-03T01:44:54Z

Pull non-MM updates from Andrew Morton: - "ida: Remove the ida_simple_xxx() API" from Christophe Jaillet completes the removal of this legacy IDR API - "panic: introduce panic status function family" from Jinchao Wang provides a number of cleanups to the panic code and its various helpers, which were rather ad-hoc and scattered all over the place - "tools/delaytop: implement real-time keyboard interaction support" from Fan Yu adds a few nice user-facing usability changes to the delaytop monitoring tool - "efi: Fix EFI boot with kexec handover (KHO)" from Evangelos Petrongonas fixes a panic which was happening with the combination of EFI and KHO - "Squashfs: performance improvement and a sanity check" from Phillip Lougher teaches squashfs's lseek() about SEEK_DATA/SEEK_HOLE. A mere 150x speedup was measured for a well-chosen microbenchmark - plus another 50-odd singleton patches all over the place * tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (75 commits) Squashfs: reject negative file sizes in squashfs_read_inode() kallsyms: use kmalloc_array() instead of kmalloc() MAINTAINERS: update Sibi Sankar's email address Squashfs: add SEEK_DATA/SEEK_HOLE support Squashfs: add additional inode sanity checking lib/genalloc: fix device leak in of_gen_pool_get() panic: remove CONFIG_PANIC_ON_OOPS_VALUE ocfs2: fix double free in user_cluster_connect() checkpatch: suppress strscpy warnings for userspace tools cramfs: fix incorrect physical page address calculation kernel: prevent prctl(PR_SET_PDEATHSIG) from racing with parent process exit Squashfs: fix uninit-value in squashfs_get_parent kho: only fill kimage if KHO is finalized ocfs2: avoid extra calls to strlen() after ocfs2_sprintf_system_inode_name() kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths sched/task.h: fix the wrong comment on task_lock() nesting with tasklist_lock coccinelle: platform_no_drv_owner: handle also built-in drivers coccinelle: of_table: handle SPI device ID tables lib/decompress: use designated initializers for struct compress_format efi: support booting with kexec handover (KHO) ...

Merge tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2025-09-30T00:48:27Z

Pull hardening updates from Kees Cook: "One notable addition is the creation of the 'transitional' keyword for kconfig so CONFIG renaming can go more smoothly. This has been a long-standing deficiency, and with the renaming of CONFIG_CFI_CLANG to CONFIG_CFI (since GCC will soon have KCFI support), this came up again. The breadth of the diffstat is mainly this renaming. - Clean up usage of TRAILING_OVERLAP() (Gustavo A. R. Silva) - lkdtm: fortify: Fix potential NULL dereference on kmalloc failure (Junjie Cao) - Add str_assert_deassert() helper (Lad Prabhakar) - gcc-plugins: Remove TODO_verify_il for GCC >= 16 - kconfig: Fix BrokenPipeError warnings in selftests - kconfig: Add transitional symbol attribute for migration support - kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI" * tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lib/string_choices: Add str_assert_deassert() helper kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI kconfig: Add transitional symbol attribute for migration support kconfig: Fix BrokenPipeError warnings in selftests gcc-plugins: Remove TODO_verify_il for GCC >= 16 stddef: Introduce __TRAILING_OVERLAP() stddef: Remove token-pasting in TRAILING_OVERLAP() lkdtm: fortify: Fix potential NULL dereference on kmalloc failure