kernel/git/stable/linux.git/mm/memblock.c, branch master

Merge tag 'liveupdate-v7.3-rc1-20260823' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux

2026-08-23T16:17:38+00:00

Pull more liveupdate updates from Mike Rapoport: "Make boot time huge page allocation work nicely with kexec handover. Today allocation of gigantic pages in HugeTLB cannot work reliably with kexec handover (KHO): - HugeTLB allocates gigantic pages using memblock and autoscaling of KHO scratch accounts for these allocations. When gigantic pages occupy half of the memory of more, KHO fails to allocate its scratch memory. - After kexec handover, memblock allocations exclusively use KHO scratch that is not supposed to contain preserved memory. This essentially blocks preservation of HugeTLB with gigantic pages. Extend early memory pools available for KHO kernel with areas that are guaranteed not to contain preserved memory" * tag 'liveupdate-v7.3-rc1-20260823' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux: (21 commits) kho: exclude hugetlb memory from scratch size calculation memblock: add memblock_reserved_hugetlb_size() memblock: make HugeTLB bootmem allocation work with KHO memblock: always include KHO headers kho: extend scratch mm/mm_init: don't rely on memblock to get KHO scratch migratetype kho: initialize preserved memory map radix tree earlier kho: initialize kho_scratch pointer earlier in boot kho: expose kho_scratch_overlap() to kexec_handover.h kho: add kho_radix_init_tree() kho: allow destroying KHO radix tree kho: allow early-boot usage of the KHO radix tree kho: add data argument to radix walk callback kho: add callback for table pages kho: add a struct for radix callbacks kho: move all memory retrieval logic to kho_mem_retrieve() kho: store incoming radix tree in kho_in kho: disallow wide keys in radix tree kho: make radix max key width more obvious kho: generalize radix tree APIs ...

Merge tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-08-21T01:17:08+00:00

Pull MM updates from Andrew Morton: - "mm: drop "sub" prefix from various places" (Dev Jain) page->folio conversion and a naming cleanup - "mm/kasan: remove redundant initialization for kasan_flag_write_only" (Igor Putko) KASAN cleanup work - "mm/filemap: reduce unnecessary xarray lookups" (Chi Zhiling) Small speedup in the pagecaache read code - "mm/percpu: Fix possible NOFS/NOIO reclaim recursion" (Kaitao Cheng) Improve the vmalloc code - mainly the avoidance of GFP_KERNEL allocations when the caller asked for GFP_NOFS or GFP_NOIO - "mm/kmemleak: avoid soft lockup when scanning task stacks" (Breno Leitao) Avoid a soft lockup watchdog trigger from the kmemleak scanning code in extreme situations - "mm/page_owner: misc cleanups" (Ye Liu) Cleanups to the page_owner code. For some reason lots of people have been working on the page_owner code this cycle. - "mm: convert to walk_page_range_vma() to eliminate find_vma()" (Kefeng Wang) Simplify and accelerate the page walking library function - "mm/migrate: preparatory cleanups for batch copy and offload" (Shivank Garg) Cleanups in the migration code - "mm/page_owner: add per-fd filter infrastructure for print_mode and NUMA filtering" (Zhen Ni) Per-fd filtering to page_owner in order to reduce the sometimes vast amount of output it can produce - "mm: Refactor bootmem gigantic hugepage allocation" (Muchun Song) Fixes and preparatory cleanups around bootmem HugeTLB handling, sparse initialization ordering, and related vmemmap setup - "mm/zsmalloc: reduce lock contention in zs_free()" (Wenchao Hao) Reduce lock contention in zs_free(), which dominates the unmap path under memory pressure on Android (LMK kills) and on x86 servers running zswap-heavy workloads. Up to 1.83x improvement in microbenchmarking. - "move alloc_tag.c file under mm/" (Suren Baghdasaryan) - "samples/damon: handle damon_{start,stop}() failures" (SJ Park) Fix improper handling of damon_start(), damon_stop(), and damon_call() failures across DAMON sample modules to prevent potential memory leaks, operation disruptions and use-after-free bugs - "mm/damon/sysfs: kobject_del() directories that users can create/remove" (SJ Park) Fix delayed sysfs directory removal under DEBUG_KOBJECT_RELEASE causeing creation failures due to duplicate directory names by adding missing kobject_del() calls before creating new directories - "mm: cleanup clear_not_present_full_ptes()" (David Hildenbrand) Clean up the core pte handling code - "selftests/damon: misc fixes for test bugs" (Kunwu Chan) Fix several bugs in the DAMON selftests - "selftests/damon: fix memcg_path staging handling" (Cheng Nie) Fix a bug in _damon_sysfs.py for damos_filter memcg_path setup, and add a test case for it in sysfs.py. - "selftests/damon: test kdamond refresh_ms" (Ruslan Valiyev) Selftest coverage for DAMON's refresh_ms sysfs feature by updating the test control module and verifying that scheme stats update automatically without manual intervention - "mm/damon: five misc fixups" (Akinobu Mita) Miscellaneous DAMON fixups. - "mm/damon/core: detect internal variation above max_nr_regions/2" (Jiayuan Chen) Fix DAMON's region splitting behavior when region counts exceed half the maximum budget by dynamically scaling down the split fraction as the limit approaches, preventing large regions from staying un-split, and add corresponding KUnit test coverage - "mm: preparatory patches for PMD level swap entries" (Usama Arif) Refactor and clean up PMD softleaf helpers, call sites, and architecture flags to lay the groundwork for a follow-up series that introduces PMD page table swap entries - "mm/damon: update, optimize, and clean up doc, tests, and code" (SJ Park) Update DAMON design and ABI documentation, expands unit and selftest coverage, optimize damon_commit_target_regions(), and clean up recently added sysfs interface code for better readability - "mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2" (Usama Arif) Optimize vmpressure() by skipping unnecessary work on cgroup v2 for userspace event notifications and refactor v1-only eventfd handling into mm/memcontrol-v1.c to reduce memory overhead and code complexity - "selftests/mm: refactor pkey helpers and fix mmap error handling" (Hongfu Li) Refactor pkeys shared tracing and assertion helpers into a common file, unify protection key selftests to use consistent diagnostic logging and assertions, and enforce standardized MAP_FAILED return checks for mmap() calls across the tests - "mm/damon: optimize out nr_accesses_bp" (SJ Park) Replace the error-prone, continuously updated nr_accesses_bp field in damon_region with an on-demand moving sum function, reducing structure memory overhead and avoiding state corruption bugs - "Open HugeTLB allocation routine for more generic use" (Ackerley Tng) Decouple HugeTLB folio allocation from VMA dependencies by introducing hugetlb_alloc_folio(), enabling subsystems like guest_memfd to allocate HugeTLB folios without standard VMA reservations or pseudo-VMAs - "mm/damon: provide pseudo moving sum probe_hits" (SJ Park) Integrate DAMON's probe_hits attribute counter into the pseudo moving sum infrastructure, enabling real-time, online monitoring without waiting for full aggregation intervals - "mm: Some cleanups for page allocator APIs" (Brendan Jackman) Simplify and refactor the page allocator entry points and flags by unifying allocation paths, adding internal alloc_flags arguments, and eliminating redundant __ prefixed alloc_pages variants. - "Fix incorrect access of hugetlb pte entries" (Dev Jain) Enforce the consistent use of huge_ptep_get() instead of ptep_get() for HugeTLB entries and fixes an unaligned address issue in arm64's huge_ptep_get() implementation - "mm/damon: validate all parameters in the core" (SJ Park) Consolidate parameter validation into the DAMON core specifically within damon_start() and damon_commit_ctx() to centralize error checking, eliminate caller-side redundant checks and to improve maintenance efficiency - "tools/mm/page_owner_sort: fix filtering and cleanup issues" (Yichong Chen) Rename is_need() to filter_record() for clearer return semantics, fix per-record allocation memory leaks and bound output copies in search_pattern() to address an existing buffer issue - "memcg: bail out reclaim when memcg is dying" (Jiayuan Chen) Mitigate a system-wide stall which occurs when a cgroup is removed while one of its memory control files is doing synchronous reclaim - "mm/memory-failure: add panic option for unrecoverable pages" (Breno Leitao) Introduce an opt-in vm.panic_on_unrecoverable_memory_failure sysctl that immediately panics the kernel on unrecoverable memory errors in kernel-owned pages to preserve error context and prevent delayed, silent data corruption - "mm/damon: refactor damon_{start,stop,commit}() for simple error handling" (SJ Park) Refactor the DAMON core API functions to guarantee that all contexts are fully stopped when damon_start(), damon_stop(), or damon_commit() fail, eliminating the need for complex and error-prone caller-side cleanup code - "Keep tail page private zero at free and folio split" (Zi Yan) Add checks to ensure tail_page->private is zero when freeing compound or high-order pages and when promoting tail pages during large folio splits. By validating these fields at free and split time, it allows the removal of redundant private field clearing inside prep_compound_tail() - "mm: drop redundant lru_add_drain in anon folio reuse paths" (Barry Song) Eliminate redundant lru_add_drain() calls in wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock contention and system overhead By validating folio refcounts against the LRU cache before draining and removing unnecessary drains in the swap path, it achieves up to a 30.5% reduction in drain calls during heavy swap workloads - "mm: clean up folio LRU and swap declarations" (Jianyue Wu) Reorganize folio LRU and swap code by relocating page-cluster state to mm/swap_state.c, renaming mm/swap.c to mm/folio.c, and moving MM-internal reclaim declarations into mm/internal.h. - "userfaultfd: working set tracking for VM guest memory" (Kiryl Shutsemau) Add userfaultfd support for tracking the working set of VM guest memory, so a VMM can identify hot pages and reclaim cold ones to tiered or remote storage - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)" (David Hildenbrand) Remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE, performing some smaller cleanups around freeing of reserved vmemmap pages on the way. - "mm/damon: update probe hits for runtime parameter commits" (SJ Park) Ensure that DAMON's probe_hits attribute counter is properly updated when monitoring intervals are changed at runtime, matching the behavior of nr_accesses. To achieve this, it refactors and renames existing helper functions for shared use, applies the updates to probe_hits, and handles edge cases in damon_probe_hits_mvsum() to maintain measurement accuracy. - "KSM: performance optimizations for rmap_walk_ksm" (xu xin) Resolve a severe KSM reverse-mapping performance bottleneck where thousands of split VMAs sharing a single anon_vma cause extended lock contention. By adding an interval-filtering check during the rmap walk, it reduces worst-case anon_vma lock hold times from over 500ms down to under 2ms, preventing application freezes and latency spikes under memory pressure. - "mm: split a couple of headers from internal.h" (Mike Rapoport) Split declarations related to mm_init, memblock, vmalloc and sparse into new headers - "KSM: use linear_page_index in collect_procs_ksm()" (xu xin) Apply the interval tree optimization from rmap_walk_ksm() to collect_procs_ksm() to avoid iterating over non-matching VMAs during KSM memory error handling. It hoists loop-invariant address initialization and restricts the anon_vma_interval_tree_foreach walk to a targeted page offset range, reducing redundant checks and improving lookup efficiency. - "selftests/mm: avoid false failures in hugetlb and KSM tests" (Sayali Patil) Fix issues in the hugetlb and KSM MM selftest categories that can report failures when the prerequisites for the tests are not satisfied - "mm/damon: introduce data attributes only monitoring" (SJ Park) Introduce attribute-weighted region management in DAMON, allowing users to prioritize specific data attributes (such as page sizes or cgroups) over or instead of access monitoring. By assigning weights to attribute probes, DAMON can completely disable access tracking and adjust monitoring regions based on weighted probe-hit counters to optimize monitoring quality for attribute-focused workloads. - "mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings" (Stanislav Kinsburskii) Extend hmm_range_fault() to support userfaultfd-backed regions by allowing the mmap lock to be dropped during fault handling via a new hmm_range_fault_locked() helper. By accepting a locked pointer and signaling retry status when lock release occurs, it enables page fault resolution in userfaultfd regions while preserving backward compatibility for existing callers. - "mm: make VMA page offset handling more consistent" (Lorenzo Stoakes) Clean up and standardize how vma->vm_pgoff is accessed and manipulated across file-backed and anonymous mappings in the kernel It introduces dedicated helper functions such as vma_start_pgoff(), vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while renaming rmap interval tree helpers to better reflect their functionality. These changes establish a cleaner foundation for future work that will unify virtual page offset indexing for all anonymous and CoW'd folios. - "mm: handle device-private PMDs in walk callbacks" (Usama Arif) Address kernel panics and state corruption caused by MM walk callbacks reaching non-present device-private PMD swap entries created during HMM migrations It ensures that functions which acquire pmd_trans_huge_lock() properly recognize device-private PMDs instead of assuming a present THP or a standard migration entry. - "mm/rmap: Refactor try_to_unmap_one" (Dev Jain) Refactor try_to_unmap_one by modularizing Hugetlb, anonymous-lazyfree, and anonymous-swapbacked logic into dedicated functions, laying the structural groundwork for batched anonymous large folio unmapping. - "Docs/ABI/damon: sysfs ABI document fixes and additions" (Song Hu) Fix typos and fills in missing entries in the DAMON sysfs ABI document - "dax/kmem: atomic whole-device hotplug via sysfs" (Gregory Price) Introduce an atomic sysfs state attribute and supporting DAX/MM infrastructure to prevent userland races when offlining and removing entire memory regions By adding an unplugged state alongside standard online modes, it enables whole-device atomic hotplug control while preserving backward compatibility. - "mm: convert more vm_flags_t users to vma_flags_t" (Lorenzo Stoakes) Continue transitioning the kernel from the deprecated vm_flags_t type to vma_flags_t across core memory management infrastructure. It replaces legacy type usage in core functions such as do_mmap(), unmapped area allocation, mm->def_vma_flags, and VMA operations like mlock, mprotect, and mremap. - "Two small patches to clean up mm/mm_slot.h" (xu xin) Refactor mm_slot.h by introducing mm_slot_remove() to unify duplicate slot deletion sequences in khugepaged and KSM. It also adds code documentation explaining why mm_slot_lookup and mm_slot_insert must remain as preprocessor macros rather than static inline functions. - "mm/damon/core: hide core-private struct fields" (SJ Park) Clean up DAMON core structures by consistently marking internal-only fields with private: comment tags to prevent improper direct access from outer layers. It enforces encapsulation across core structures including damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to interact through approved access APIs instead of exposing raw struct members. - "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races" (SJ Park) Address potential infinite loops, NULL dereferences, and race conditions identified in DAMON It fixes an infinite loop triggered by extreme user configurations, a NULL pointer dereference within unit tests and minor monitoring accuracy degradation caused by subtle runtime races. - "mm/page_alloc: fixes for free_pages_nolock() on RT/UP" (Brendan Jackman) Fix an NMI safety flaw in __free_frozen_pages() where freeing pages on non-SMP or PREEMPT_RT kernels can bypass can_spin_trylock() checks via non-PCP or isolated migration paths. It also resolves potential kernel crashes and privilege escalation risks triggered when BPF tracing runs in NMI context alongside memory hotplug or large allocation frees. - "mm/page_alloc: couple of followups for recent cleanups" (Brendan Jackman) Clean up and update page allocator nomenclature, documentation, and debug assertions. It aligns internal FPI_ flags with the public "nolock" naming convention, removes outdated internal implementation details from high-level page allocator comments, and eliminates obsolete VM_BUG_ON() assertions in allocation paths. - "mm/mseal: further cleanups" (Lorenzo Stoakes) Refactor and simplify the mseal implementation by clarifying API boundaries and removing unnecessary code complexity. It replaces generic do_mseal() usage outside the syscall with a dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO, eliminates mm_struct parameters to enforce that sealing applies only to current->mm, and streamlines overall logic and comments with no functional changes intended. - "mm/vmscan: fix swappiness=max and clean up per-node proactive reclaim" (Ridong Chen) Resolve reclaim behavior bugs and clean up function parameters across memory reclaim paths It fixes swappiness=max in both standard reclaim and MGLRU so unswappable anonymous memory no longer falls back to evicting page cache, ensures reclaim_store() returns accurate error codes instead of collapsing all failures into -EAGAIN, and removes the obsolete gfp_mask parameter from __node_reclaim(). - "mm: mincore: misc cleanups" (Kefeng Wang) Clean up and simplifies the mincore code. Most importantly, it removes the historical special behavior that always reports VM_PFNMAP pages as non-resident. - "mm/huge_memory: drop dead split helper variants" (Kiryl Shutsemau) Two trivial cleanups in the folio split API - "mm/damon: fix uninitialized DAMOS field and kunit exec expectation bugs" (SJ Park) Resolve minor operational and testing bugs in DAMON identified by Sashiko. It initializes the damos->last_applied field to prevent occasional efficiency degradation and fixes invalid memory accesses in DAMON KUnit tests during test failure handling. - "cleanup for stable_page_flags()" (Jinjiang Tu) Clean up and refactor stable_page_flags() used by /proc/kpageflags without altering functionality. It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag bits, converts folio-specific flag checks to standard folio_test_*() helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling. - "Batch unmap of uffd-wp file folios" (Dev Jain) Extend batched folio unmapping support to file folios within userfaultfd write-protect (uffd-wp) VMAs by adding batching capabilities to pte_install_uffd_wp_if_needed(). This removes special-case restrictions on uffd-wp VMAs in try_to_unmap_one(), significantly simplifying the function's control flow and complexity. - "mm/early_ioremap: clarify and clean up early_ioremap_reset()" (Sang-Heon Jeon) Clarify and clean up the architecture-specific usage of __late_set_fixmap() and __late_clear_fixmap() after early_ioremap_reset() It adds explicit documentation regarding when early_ioremap_reset() must be called and removes redundant macro definitions and reset calls in the RISC-V and ARM64 architectures. - "mm: fix reclaim storms in defrag_mode" (Johannes Weiner) Address severe performance regressions, swap storms, and spurious OOMs caused by vm.defrag_mode=1 under high memory pressure in Meta production It updates the page allocator slowpath so non-movable allocation requests actively trigger direct reclaim and direct compaction at pageblock_order scale, allowing them to claim whole pageblocks rather than spinning unproductively. - "zram: lockmap tweaks" (Sebastian Siewior) Optimize and fix lockdep tracking for zram devices by consolidating per-entry lockmaps and isolate lock classes across multiple instances This reduces memory overhead by replacing per-entry lockdep_map instances with a single map per struct zram, and assigns a dynamic lock_class_key to each instance to prevent false deadlock reports when different zram devices are backed by distinct filesystems. * tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (501 commits) selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check selftests/mm: unpoison pages in memory-failure teardown mm/shmem: downgrade final i_blocks check in shmem_evict_inode() to pr_warn() mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro mm/zsmalloc: fix release order of locks in zs_page_migrate() Documentation: zram: remove sections numbering ksm: stop iterating VMAs when ksm_test_exit returns true mm: fold userfaultfd_rwp() to false without CONFIG_ARCH_HAS_PTE_PROTNONE mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch() zram: use a custom key for each zram object zram: move lockmap to be per-zram instead per table selftests/mm: fix gup_longterm EINVAL error message mm: page_alloc: fix non-movable reclaim storm in defrag_mode mm: page_alloc: move capture_control to the page allocator mm: compaction: support non-movable compaction for pageblock requests mm: page_alloc: __GFP_FS lockdep annotation for direct compaction hugetlb: evaluate subpool free state while locked mm/damon: remove trailing semicolons after function definitions mm/damon/ops-common: prevent migration fallback to non-target nodes mm/damon: update outdated comment about DAMOS filter handling ...

mm: split out mm_init and memblock declarations from internal.h

2026-08-05T02:18:45+00:00

Patch series "mm: split a couple of headers from internal.h", v2. mm/internal.h becomes more and more bloated. Split declarations related to mm_init, memblock, vmalloc and sparse into new headers. This patch (of 3): mm/internal.h becomes more and more bloated. Move declarations for related to mm/mm_init.c and mm/memblock.c to a new mm/mm_init.h header. No functional changes. [rppt@kernel.org: split stubfs from internal.h to mm_init.h] Link: https://lore.kernel.org/alJd1BLypyK9Mpaw@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-0-695631425968@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-1-695631425968@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Muchun Song Acked-by: Vlastimil Babka (SUSE) Acked-by: David Hildenbrand (Arm) Acked-by: Lorenzo Stoakes Acked-by: Pratyush Yadav Acked-by: SJ Park Cc: Alexander Graf Cc: Alexander Potapenko Cc: Brendan Jackman Cc: Brendan Jackman Cc: Dennis Zhou Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Liam R. Howlett Cc: Marco Elver Cc: Michal Hocko Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Suren Baghdasaryan Cc: Tejun Heo Cc: "Uladzislau Rezki (Sony)" Cc: Zi Yan Signed-off-by: Andrew Morton

memblock: add memblock_reserved_hugetlb_size()

2026-08-04T06:29:03+00:00

Similar to memblock_reserved_kern_size(), but calculates only the memory reserved for hugetlb pages. This is needed in an upcoming commit that subtracts hugetlb reservation size when computing the size of KHO scratch areas. Signed-off-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260801084833.1897543-22-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft)

memblock: make HugeTLB bootmem allocation work with KHO

2026-08-04T06:28:39+00:00

Gigantic huge page allocation is somewhat broken currently when KHO is used. Firstly, they break KHO scratch size accounting. RSRV_KERN is used to track how much memory is reserved for use by the kernel. Since hugetlb::alloc_bootmem() calls the memblock_alloc*() APIs, the hugepages allocated also get marked as RSRV_KERN. Allocations marked RSRV_KERN are used by KHO to calculate how much scratch space it should reserve to make sure the next kernel has enough memory to boot when it is in scratch-only phase. Counting hugepages in that blows up scratch size, and can lead to the scratch allocation failing, making KHO unusable. This will show up when huge pages make up more than 50% of the system, which is a fairly common use case. Secondly, while not supported right now, huge pages are user memory and can be preserved via KHO. The scratch spaces should not have any preserved memory. Allocating hugepages from scratch (on a KHO boot) can lead to them being un-preservable. Introduce memblock_alloc_hugetlb(). This lets memblock tailor to the needs of hugetb without exposing those details to the general allocation routines. First, it does not use mirrored memory for hugetlb. Mirrored memory is a limited resource that is best saved for kernel data structures, not user memory. Second, if the free memory area found by memblock_find_in_range_node() is a part of a KHO scratch area, the free area is not used. Allocation is retried starting after the free area to ensure no hugepages come from KHO scratch. Third, it simplifies the argument list by baking in some hugetlb assumptions like alignment and exact_nid. This also simplifies allocation logic in alloc_bootmem(). Also introduce MEMBLOCK_RSRV_HUGETLB to mark reservations made for HugeTLB. This will be used by KHO in future patches to correctly calculate scratch sizes. Refactor some of the preparation logic like kmemleak tracking and accepting memory into a separate helper memblock_prep_allocation(), and use it from both memblock_alloc_hugetlb() and the usual memblock_alloc_range_nid(). Signed-off-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260801084833.1897543-21-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft)

memblock: always include KHO headers

2026-08-04T06:28:18+00:00

In a coming commit, memblock will start using kho_scratch_overlap() without a compile guard. The compile guard for the function is in kexec_handover.h and provides a stub when CONFIG_KEXEC_HANDOVER is disabled. Since in memblock the call will exist unconditionally, always include the KHO headers. Including these headers unconditionally breaks memblock test compilation. Add stubs to fix that. Signed-off-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260801084833.1897543-20-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft)

mm/mm_init: don't rely on memblock to get KHO scratch migratetype

2026-08-04T06:25:55+00:00

Currently struct page init via memmap_init() or deferred_init_memmap() only queries the migrate type from KHO for each discrete memory range. That works currently since KHO scratch memory has a different memory type so it is always it its own region. An upcoming patch will add support for discovering blocks of memory with no preservations and it will mark it as MEMBLOCK_KHO_SCRATCH to allow allocations from them. This can lead to the bootmem KHO scratch areas to be merged into larger free ranges. This merging breaks the selection of migrate type. Get rid of memblock_is_kho_scratch_memory(). Instead, use kho_scratch_overlap() to decide the migrate type of the PFN. Since kho_scratch_migratetype() only uses KHO functions, move it to kexec_handover.h. Instead of calling kho_scratch_migratetype() once for each free range, call it once for each pageblock. Update pageblock_migratetype_init_range() and memmap_init_range() to do so. Since the migrate type is now evaluated for each pageblock and not each free range, drop the migratetype arguments to deferred_free_pages() and memmap_init_zone_range() and use MIGRATE_MOVABLE directly. Signed-off-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260801084833.1897543-18-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft)

mm/memblock: Remove redundant pageblock_align() in free_unused_memmap()

2026-06-30T08:34:55+00:00

The assignment `prev_end = pageblock_align(end)` is redundant because `prev_end` was already aligned to pageblock oundaries inside the loop. Since pageblock_align() is a pure function, calling it again with the same input produces the same result. This line was added in commit f921f53e089a ("memblock: align freed memory map on pageblock boundaries with SPARSEMEM"). Remove it to simplify the code. Signed-off-by: Zhen Ni Link: https://patch.msgid.link/20260612031105.3350181-1-zhen.ni@easystack.cn Signed-off-by: Mike Rapoport (Microsoft)

kho: fix deferred initialization of scratch areas

2026-05-31T23:31:37+00:00

Currently, if CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, kho_release_scratch() will initialize the struct pages and set migratetype of KHO scratch. Unless the whole scratch fits below first_deferred_pfn, some of that will be overwritten either by deferred_init_pages() or memmap_init_reserved_range(). To fix it, make memmap_init_range(), deferred_init_memmap_chunk() and __init_page_from_nid() recognize KHO scratch regions and set migratetype of pageblocks in those regions to MIGRATE_CMA. Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Michal Clapinski Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pasha Tatashin Reviewed-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260423122538.140993-2-mclapinski@google.com Signed-off-by: Mike Rapoport (Microsoft)

memblock: don't touch memblock arrays when memblock_free() is called late

2026-05-25T17:48:14+00:00

When memblock_free() is called after memblock_discard() on architectures that don't select ARCH_KEEP_MEMBLOCK, it tries to update memblock.reserved that was already discarded and it causes use-after-free, for example [ 8.514775] BUG: KASAN: use-after-free in memblock_isolate_range+0x4ac/0x650 [ 8.514775] Read of size 8 at addr ffff88a07fe6a000 by task swapper/0/1 [ 8.514775] Call Trace: [ 8.514775] [ 8.514775] kasan_report+0xb2/0x1b0 [ 8.514775] memblock_isolate_range+0x4ac/0x650 [ 8.514775] memblock_phys_free+0xc4/0x190 [ 8.514775] housekeeping_late_init+0x257/0x280 [ 8.514775] do_one_initcall+0xaa/0x470 [ 8.514775] do_initcalls+0x1b4/0x1f0 [ 8.514775] kernel_init_freeable+0x4b5/0x550 [ 8.514775] kernel_init+0x1c/0x150 [ 8.514775] ret_from_fork+0x5dc/0x8e0 [ 8.514775] ret_from_fork_asm+0x1a/0x30 [ 8.514775] Make sure memblock_free() updates memblock.reserved only when called early enough or when ARCH_KEEP_MEMBLOCK is enabled. Reported-by: Waiman Long Reported-by: Breno Leitao Closes: https://lore.kernel.org/all/20260505051821.1107133-1-longman@redhat.com Tested-by: Waiman Long Tested-by: Breno Leitao Fixes: 87ce9e83ab8b ("memblock, treewide: make memblock_free() handle late freeing") Link: https://patch.msgid.link/20260513105122.502506-1-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft)