kernel/linux.git/include/linux/vmalloc.h, branch v6.19.11

mm/vmalloc: handle non-blocking GFP in __vmalloc_area_node()

2025-11-17T01:27:54+00:00

Make __vmalloc_area_node() respect non-blocking GFP masks such as GFP_ATOMIC and GFP_NOWAIT. - Add memalloc_apply_gfp_scope()/memalloc_restore_scope() helpers to apply a proper scope. - Apply memalloc_apply_gfp_scope()/memalloc_restore_scope() around vmap_pages_range() for page table setup. - Set "nofail" to false if a non-blocking mask is used, as they are mutually exclusive. This is particularly important for page table allocations that internally use GFP_PGTABLE_KERNEL, which may sleep unless such scope restrictions are applied. For example: __pte_alloc_kernel() pte_alloc_one_kernel(&init_mm); pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM, 0); Note: in most cases, PTE entries are established only up to the level required by current vmap space usage, meaning the page tables are typically fully populated during the mapping process. Link: https://lkml.kernel.org/r/20251007122035.56347-6-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Acked-by: Michal Hocko Reviewed-by: Baoquan He Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Marco Elver Cc: Michal Hocko Signed-off-by: Andrew Morton

mm/vmalloc: defer freeing partly initialized vm_struct

2025-11-17T01:27:53+00:00

__vmalloc_area_node() may call free_vmap_area() or vfree() on error paths, both of which can sleep. This becomes problematic if the function is invoked from an atomic context, such as when GFP_ATOMIC or GFP_NOWAIT is passed via gfp_mask. To fix this, unify error paths and defer the cleanup of partly initialized vm_struct objects to a workqueue. This ensures that freeing happens in a process context and avoids invalid sleeps in atomic regions. Link: https://lkml.kernel.org/r/20251007122035.56347-5-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Acked-by: Michal Hocko Reviewed-by: Baoquan He Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Marco Elver Cc: Michal Hocko Signed-off-by: Andrew Morton

mm/vmalloc: allow to set node and align in vrealloc

2025-09-13T23:54:45+00:00

Patch series "support large align and nid in Rust allocators", v15. The series provides the ability for Rust allocators to set NUMA node and large alignment. This patch (of 4): Reimplement vrealloc() to be able to set node and alignment should a user need to do so. Rename the function to vrealloc_node_align() to better match what it actually does now and introduce macros for vrealloc() and friends for backward compatibility. With that change we also provide the ability for the Rust part of the kernel to set node and alignment in its allocations. Link: https://lkml.kernel.org/r/20250806124034.1724515-1-vitaly.wool@konsulko.se Link: https://lkml.kernel.org/r/20250806124108.1724561-1-vitaly.wool@konsulko.se Signed-off-by: Vitaly Wool Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Vlastimil Babka Cc: Alice Ryhl Cc: Danilo Krummrich Cc: Herbert Xu Cc: Jann Horn Cc: Kent Overstreet Cc: Liam Howlett Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton

mm: move page table sync declarations to linux/pgtable.h

2025-08-28T05:45:44+00:00

During our internal testing, we started observing intermittent boot failures when the machine uses 4-level paging and has a large amount of persistent memory: BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...] It turns out that the kernel panics while initializing vmemmap (struct page array) when the vmemmap region spans two PGD entries, because the new PGD entry is only installed in init_mm.pgd, but not in the page tables of other tasks. And looking at __populate_section_memmap(): if (vmemmap_can_optimize(altmap, pgmap)) // does not sync top level page tables r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); else // sync top level page tables in x86 r = vmemmap_populate(start, end, nid, altmap); In the normal path, vmemmap_populate() in arch/x86/mm/init_64.c synchronizes the top level page table (See commit 9b861528a801 ("x86-64, mem: Update all PGDs for direct mapping and vmemmap mapping changes")) so that all tasks in the system can see the new vmemmap area. However, when vmemmap_can_optimize() returns true, the optimized path skips synchronization of top-level page tables. This is because vmemmap_populate_compound_pages() is implemented in core MM code, which does not handle synchronization of the top-level page tables. Instead, the core MM has historically relied on each architecture to perform this synchronization manually. We're not the first party to encounter a crash caused by not-sync'd top level page tables: earlier this year, Gwan-gyeong Mun attempted to address the issue [1] [2] after hitting a kernel panic when x86 code accessed the vmemmap area before the corresponding top-level entries were synced. At that time, the issue was believed to be triggered only when struct page was enlarged for debugging purposes, and the patch did not get further updates. It turns out that current approach of relying on each arch to handle the page table sync manually is fragile because 1) it's easy to forget to sync the top level page table, and 2) it's also easy to overlook that the kernel should not access the vmemmap and direct mapping areas before the sync. # The solution: Make page table sync more code robust and harder to miss To address this, Dave Hansen suggested [3] [4] introducing {pgd,p4d}_populate_kernel() for updating kernel portion of the page tables and allow each architecture to explicitly perform synchronization when installing top-level entries. With this approach, we no longer need to worry about missing the sync step, reducing the risk of future regressions. The new interface reuses existing ARCH_PAGE_TABLE_SYNC_MASK, PGTBL_P*D_MODIFIED and arch_sync_kernel_mappings() facility used by vmalloc and ioremap to synchronize page tables. pgd_populate_kernel() looks like this: static inline void pgd_populate_kernel(unsigned long addr, pgd_t *pgd, p4d_t *p4d) { pgd_populate(&init_mm, pgd, p4d); if (ARCH_PAGE_TABLE_SYNC_MASK & PGTBL_PGD_MODIFIED) arch_sync_kernel_mappings(addr, addr); } It is worth noting that vmalloc() and apply_to_range() carefully synchronizes page tables by calling p*d_alloc_track() and arch_sync_kernel_mappings(), and thus they are not affected by this patch series. This series was hugely inspired by Dave Hansen's suggestion and hence added Suggested-by: Dave Hansen. Cc stable because lack of this series opens the door to intermittent boot failures. This patch (of 3): Move ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to linux/pgtable.h so that they can be used outside of vmalloc and ioremap. Link: https://lkml.kernel.org/r/20250818020206.4517-1-harry.yoo@oracle.com Link: https://lkml.kernel.org/r/20250818020206.4517-2-harry.yoo@oracle.com Link: https://lore.kernel.org/linux-mm/20250220064105.808339-1-gwan-gyeong.mun@intel.com [1] Link: https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [2] Link: https://lore.kernel.org/linux-mm/d1da214c-53d3-45ac-a8b6-51821c5416e4@intel.com [3] Link: https://lore.kernel.org/linux-mm/4d800744-7b88-41aa-9979-b245e8bf794b@intel.com [4] Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges") Signed-off-by: Harry Yoo Acked-by: Kiryl Shutsemau Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: "Uladzislau Rezki (Sony)" Reviewed-by: Lorenzo Stoakes Acked-by: David Hildenbrand Cc: Alexander Potapenko Cc: Alistair Popple Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: "Aneesh Kumar K.V" Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: bibo mao Cc: Borislav Betkov Cc: Christoph Lameter (Ampere) Cc: Dennis Zhou Cc: Dev Jain Cc: Dmitriy Vyukov Cc: Gwan-gyeong Mun Cc: Ingo Molnar Cc: Jane Chu Cc: Joao Martins Cc: Joerg Roedel Cc: John Hubbard Cc: Kevin Brodsky Cc: Liam Howlett Cc: Michal Hocko Cc: Oscar Salvador Cc: Peter Xu Cc: Peter Zijlstra Cc: Qi Zheng Cc: Ryan Roberts Cc: Suren Baghdasaryan Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Huth Cc: Vincenzo Frascino Cc: Vlastimil Babka Cc: Dave Hansen Cc: Signed-off-by: Andrew Morton

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2025-05-28T21:55:35+00:00

Pull arm64 updates from Will Deacon: "The headline feature is the re-enablement of support for Arm's Scalable Matrix Extension (SME) thanks to a bumper crop of fixes from Mark Rutland. If matrices aren't your thing, then Ryan's page-table optimisation work is much more interesting. Summary: ACPI, EFI and PSCI: - Decouple Arm's "Software Delegated Exception Interface" (SDEI) support from the ACPI GHES code so that it can be used by platforms booted with device-tree - Remove unnecessary per-CPU tracking of the FPSIMD state across EFI runtime calls - Fix a node refcount imbalance in the PSCI device-tree code CPU Features: - Ensure register sanitisation is applied to fields in ID_AA64MMFR4 - Expose AIDR_EL1 to userspace via sysfs, primarily so that KVM guests can reliably query the underlying CPU types from the VMM - Re-enabling of SME support (CONFIG_ARM64_SME) as a result of fixes to our context-switching, signal handling and ptrace code Entry code: - Hook up TIF_NEED_RESCHED_LAZY so that CONFIG_PREEMPT_LAZY can be selected Memory management: - Prevent BSS exports from being used by the early PI code - Propagate level and stride information to the low-level TLB invalidation routines when operating on hugetlb entries - Use the page-table contiguous hint for vmap() mappings with VM_ALLOW_HUGE_VMAP where possible - Optimise vmalloc()/vmap() page-table updates to use "lazy MMU mode" and hook this up on arm64 so that the trailing DSB (used to publish the updates to the hardware walker) can be deferred until the end of the mapping operation - Extend mmap() randomisation for 52-bit virtual addresses (on par with 48-bit addressing) and remove limited support for randomisation of the linear map Perf and PMUs: - Add support for probing the CMN-S3 driver using ACPI - Minor driver fixes to the CMN, Arm-NI and amlogic PMU drivers Selftests: - Fix FPSIMD and SME tests to align with the freshly re-enabled SME support - Fix default setting of the OUTPUT variable so that tests are installed in the right location vDSO: - Replace raw counter access from inline assembly code with a call to the the __arch_counter_get_cntvct() helper function Miscellaneous: - Add some missing header inclusions to the CCA headers - Rework rendering of /proc/cpuinfo to follow the x86-approach and avoid repeated buffer expansion (the user-visible format remains identical) - Remove redundant selection of CONFIG_CRC32 - Extend early error message when failing to map the device-tree blob" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (83 commits) arm64: cputype: Add cputype definition for HIP12 arm64: el2_setup.h: Make __init_el2_fgt labels consistent, again perf/arm-cmn: Add CMN S3 ACPI binding arm64/boot: Disallow BSS exports to startup code arm64/boot: Move global CPU override variables out of BSS arm64/boot: Move init_pgdir[] and init_idmap_pgdir[] into __pi_ namespace perf/arm-cmn: Initialise cmn->cpu earlier kselftest/arm64: Set default OUTPUT path when undefined arm64: Update comment regarding values in __boot_cpu_mode arm64: mm: Drop redundant check in pmd_trans_huge() arm64/mm: Re-organise setting up FEAT_S1PIE registers PIRE0_EL1 and PIR_EL1 arm64/mm: Permit lazy_mmu_mode to be nested arm64/mm: Disable barrier batching in interrupt contexts arm64/cpuinfo: only show one cpu's info in c_show() arm64/mm: Batch barriers when updating kernel mappings mm/vmalloc: Enter lazy mmu mode while manipulating vmalloc ptes arm64/mm: Support huge pte-mapped pages in vmap mm/vmalloc: Gracefully unmap huge ptes mm/vmalloc: Warn on improper use of vunmap_range() arm64/mm: Hoist barriers out of set_ptes_anysz() loop ...

Merge tag 'locking-core-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-05-26T21:42:07+00:00

Pull locking updates from Ingo Molnar: "Futexes: - Add support for task local hash maps (Sebastian Andrzej Siewior, Peter Zijlstra) - Implement the FUTEX2_NUMA ABI, which feature extends the futex interface to be NUMA-aware. On NUMA-aware futexes a second u32 word containing the NUMA node is added to after the u32 futex value word (Peter Zijlstra) - Implement the FUTEX2_MPOL ABI, which feature extends the futex interface to be mempolicy-aware as well, to further refine futex node mappings and lookups (Peter Zijlstra) Locking primitives: - Misc cleanups (Andy Shevchenko, Borislav Petkov, Colin Ian King, Ingo Molnar, Nam Cao, Peter Zijlstra) Lockdep: - Prevent abuse of lockdep subclasses (Waiman Long) - Add number of dynamic keys to /proc/lockdep_stats (Waiman Long) Plus misc cleanups and fixes" * tag 'locking-core-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits) selftests/futex: Fix spelling mistake "unitiliazed" -> "uninitialized" futex: Correct the kernedoc return value for futex_wait_setup(). tools headers: Synchronize prctl.h ABI header futex: Use RCU_INIT_POINTER() in futex_mm_init(). selftests/futex: Use TAP output in futex_numa_mpol selftests/futex: Use TAP output in futex_priv_hash futex: Fix kernel-doc comments futex: Relax the rcu_assign_pointer() assignment of mm->futex_phash in futex_mm_init() futex: Fix outdated comment in struct restart_block locking/lockdep: Add number of dynamic keys to /proc/lockdep_stats locking/lockdep: Prevent abuse of lockdep subclass locking/lockdep: Move hlock_equal() to the respective #ifdeffery futex,selftests: Add another FUTEX2_NUMA selftest selftests/futex: Add futex_numa_mpol selftests/futex: Add futex_priv_hash selftests/futex: Build without headers nonsense tools/perf: Allow to select the number of hash buckets tools headers: Synchronize prctl.h ABI header futex: Implement FUTEX2_MPOL futex: Implement FUTEX2_NUMA ...

mm/vmalloc: Gracefully unmap huge ptes

2025-05-09T12:43:07+00:00

Commit f7ee1f13d606 ("mm/vmalloc: enable mapping of huge pages at pte level in vmap") added its support by reusing the set_huge_pte_at() API, which is otherwise only used for user mappings. But when unmapping those huge ptes, it continued to call ptep_get_and_clear(), which is a layering violation. To date, the only arch to implement this support is powerpc and it all happens to work ok for it. But arm64's implementation of ptep_get_and_clear() can not be safely used to clear a previous set_huge_pte_at(). So let's introduce a new arch opt-in function, arch_vmap_pte_range_unmap_size(), which can provide the size of a (present) pte. Then we can call huge_ptep_get_and_clear() to tear it down properly. Note that if vunmap_range() is called with a range that starts in the middle of a huge pte-mapped page, we must unmap the entire huge page so the behaviour is consistent with pmd and pud block mappings. In this case emit a warning just like we do for pmd/pud mappings. Reviewed-by: Anshuman Khandual Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Catalin Marinas Signed-off-by: Ryan Roberts Tested-by: Luiz Capitulino Link: https://lore.kernel.org/r/20250422081822.1836315-9-ryan.roberts@arm.com Signed-off-by: Will Deacon

mm: vmalloc: support more granular vrealloc() sizing

2025-05-08T06:39:41+00:00

Introduce struct vm_struct::requested_size so that the requested (re)allocation size is retained separately from the allocated area size. This means that KASAN will correctly poison the correct spans of requested bytes. This also means we can support growing the usable portion of an allocation that can already be supported by the existing area's existing allocation. Link: https://lkml.kernel.org/r/20250426001105.it.679-kees@kernel.org Fixes: 3ddc2fefe6f3 ("mm: vmalloc: implement vrealloc()") Signed-off-by: Kees Cook Reported-by: Erhard Furtner Closes: https://lore.kernel.org/all/20250408192503.6149a816@outsider.home/ Reviewed-by: Danilo Krummrich Cc: Michal Hocko Cc: "Uladzislau Rezki (Sony)" Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

mm: Add vmalloc_huge_node()

2025-05-03T10:02:05+00:00

To enable node specific hash-tables using huge pages if possible. [bigeasy: use __vmalloc_node_range_noprof(), add nommu bits, inline vmalloc_huge] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250416162921.513656-3-bigeasy@linutronix.de

alloc_tag: populate memory for module tags as needed

2024-11-07T22:25:16+00:00

The memory reserved for module tags does not need to be backed by physical pages until there are tags to store there. Change the way we reserve this memory to allocate only virtual area for the tags and populate it with physical pages as needed when we load a module. [surenb@google.com: avoid execmem_vmap() when !MMU] Link: https://lkml.kernel.org/r/20241031233611.3833002-1-surenb@google.com Link: https://lkml.kernel.org/r/20241023170759.999909-5-surenb@google.com Signed-off-by: Suren Baghdasaryan Reviewed-by: Pasha Tatashin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Borislav Petkov (AMD) Cc: Christoph Hellwig Cc: Daniel Gomez Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joonsoo Kim Cc: Kalesh Singh Cc: Kees Cook Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Luis Chamberlain Cc: Matthew Wilcox Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Minchan Kim Cc: Paul E. McKenney Cc: Petr Pavlu Cc: Roman Gushchin Cc: Sami Tolvanen Cc: Sourav Panda Cc: Steven Rostedt (Google) Cc: Thomas Gleixner Cc: Thomas Huth Cc: Uladzislau Rezki (Sony) Cc: Vlastimil Babka Cc: Xiongwei Song Cc: Yu Zhao Signed-off-by: Andrew Morton