wireguard-linux/arch/x86/entry/vdso, branch stable

x86/vdso: Respect COMPAT_32BIT_TIME

2026-07-07T21:52:53Z

If CONFIG_COMPAT_32BIT_TIME is disabled then the vDSO should not provide any 32-bit time related functionality. This is the intended effect of the kconfig option and also the fallback system calls would also not be implemented. Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Reviewed-by: Arnd Bergmann Link: https://patch.msgid.link/20260702-vdso-compat_32bit_time-v3-3-db9f36d8d432@linutronix.de

Merge tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

2026-06-15T08:51:14Z

Pull locking updates from Ingo Molnar: "Futex updates: - Optimize futex hash bucket access patterns (Peter Zijlstra) - Large series to address the robust futex unlock race for real, by Thomas Gleixner: "The robust futex unlock mechanism is racy in respect to the clearing of the robust_list_head::list_op_pending pointer because unlock and clearing the pointer are not atomic. The race window is between the unlock and clearing the pending op pointer. If the task is forced to exit in this window, exit will access a potentially invalid pending op pointer when cleaning up the robust list. That happens if another task manages to unmap the object containing the lock before the cleanup, which results in an UAF. In the worst case this UAF can lead to memory corruption when unrelated content has been mapped to the same address by the time the access happens. User space can't solve this problem without help from the kernel. This series provides the kernel side infrastructure to help it along: 1) Combined unlock, pointer clearing, wake-up for the contended case 2) VDSO based unlock and pointer clearing helpers with a fix-up function in the kernel when user space was interrupted within the critical section. ... with help by André Almeida: - Add a note about robust list race condition (André Almeida) - Add self-tests for robust release operations (André Almeida) Context analysis updates: - Implement context analysis for 'struct rt_mutex'. (Bart Van Assche) - Bump required Clang version to 23 (Marco Elver) Guard infrastructure updates: - Series to remove NULL check from unconditional guards (Dmitry Ilvokhin) Lockdep updates: - Restore self-test migrate_disable() and sched_rt_mutex state on PREEMPT_RT (Karl Mehltretter) Membarriers updates: - Use per-CPU mutexes for targeted commands (Aniket Gattani) - Modernize membarrier_global_expedited with cleanup guards (Aniket Gattani) - Add rseq stress test for CFS throttle interactions (Aniket Gattani) percpu-rwsems updates: - Extract __percpu_up_read() to optimize inlining overhead (Dmitry Ilvokhin) Seqlocks updates: - Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens) Lock tracing: - Add contended_release tracepoint to sleepable locks such as mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry Ilvokhin) MAINTAINERS updates: - MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng) Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra, Dmitry Ilvokhin and Peter Zijlstra" * tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits) locking: Add contended_release tracepoint to sleepable locks locking/percpu-rwsem: Extract __percpu_up_read() tracing/lock: Remove unnecessary linux/sched.h include futex: Optimize futex hash bucket access patterns rust: sync: completion: Mark inline complete_all and wait_for_completion MAINTAINERS: Add RUST [SYNC] entry cleanup: Specify nonnull argument index selftests: futex: Add tests for robust release operations Documentation: futex: Add a note about robust list race condition x86/vdso: Implement __vdso_futex_robust_try_unlock() x86/vdso: Prepare for robust futex unlock support futex: Provide infrastructure to plug the non contended robust futex unlock race futex: Add robust futex unlock IP range futex: Add support for unlocking robust futexes futex: Cleanup UAPI defines x86: Select ARCH_MEMORY_ORDER_TSO uaccess: Provide unsafe_atomic_store_release_user() futex: Provide UABI defines for robust list entry modifiers futex: Move futex related mm_struct data into a struct futex: Make futex_mm_init() void ...

Merge tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

2026-06-14T23:31:15Z

Pull Kbuild / Kconfig updates from Nathan Chancellor: "Kbuild: - Remove broken module linking exclusion for BTF - Add documentation around how offset header files work - Include unstripped vDSO libraries in pacman packages - Bump minimum version of LLVM for building the kernel to 17.0.1 and clean up unnecessary workarounds - Use a context manager in run-clang-tools - Add dist macro value if present to release tag for RPM packages - Detect and report truncated buf_printf() output in modpost - Add __llvm_covfun and __llvm_covmap to section whitelist in modpost - Support Clang's distributed ThinLTO mode - Remove architecture specific configurations for AutoFDO and Propeller to ease individual architecture maintenance Kconfig: - Add kconfig-sym-check target to look for dangling Kconfig symbol references and invalid tristate literal values - Harden against potential NULL pointer dereference - Fix typo in Kconfig test comment" * tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (31 commits) kconfig: tests: fix typo in comment kconfig: Remove the architecture specific config for Propeller kconfig: Remove the architecture specific config for AutoFDO modpost: Add __llvm_covfun and __llvm_covmap to section_white_list kconfig: add kconfig-sym-check static checker kbuild: Remove unnecessary 'T' modifier in cmd_ar_builtin_fixup kbuild: distributed build support for Clang ThinLTO kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a scripts: modpost: detect and report truncated buf_printf() output kbuild: rpm-pkg: append %{?dist} macro to Release tag run-clang-tools: run multiprocessing.Pool as context manager compiler-clang.h: Drop explicit version number from "all" diagnostic macro compiler-clang.h: Remove __cleanup -Wunused-variable workaround kbuild: Remove check for broken scoping with clang < 17 in CC_HAS_ASM_GOTO_OUTPUT x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags' x86/module: Revert "Deal with GOT based stack cookie load on Clang < 17" x86/build: Drop unnecessary '-ffreestanding' addition to KBUILD_CFLAGS scripts/Makefile.warn: Drop -Wformat handling for clang < 16 riscv: Drop tautological condition from TOOLCHAIN_NEEDS_OLD_ISA_SPEC riscv: Remove tautological condition from selection of ARCH_SUPPORTS_CFI ...

x86/vdso: Implement __vdso_futex_robust_try_unlock()

2026-06-03T09:38:52Z

When the FUTEX_ROBUST_UNLOCK mechanism is used for unlocking (PI-)futexes, then the unlock sequence in userspace looks like this: 1) robust_list_set_op_pending(mutex); 2) robust_list_remove(mutex); lval = gettid(); 3) if (atomic_try_cmpxchg(&mutex->lock, lval, 0)) 4) robust_list_clear_op_pending(); else 5) sys_futex(OP,...FUTEX_ROBUST_UNLOCK); That still leaves a minimal race window between #3 and #4 where the mutex could be acquired by some other task which observes that it is the last user and: 1) unmaps the mutex memory 2) maps a different file, which ends up covering the same address When then the original task exits before reaching #5 then the kernel robust list handling observes the pending op entry and tries to fix up user space. In case that the newly mapped data contains the TID of the exiting thread at the address of the mutex/futex the kernel will set the owner died bit in that memory and therefore corrupt unrelated data. Provide a VDSO function which exposes the critical section window in the VDSO symbol table. The resulting addresses are updated in the task's mm when the VDSO is (re)map()'ed. The core code detects when a task was interrupted within the critical section and is about to deliver a signal. It then invokes an architecture specific function which determines whether the pending op pointer has to be cleared or not. The unlock assembly sequence on 64-bit is: mov %esi,%eax // Load TID into EAX xor %ecx,%ecx // Set ECX to 0 lock cmpxchg %ecx,(%rdi) // Try the TID -> 0 transition .Lstart: jnz .Lend movq %rcx,(%rdx) // Clear list_op_pending .Lend: ret So the decision can be simply based on the ZF state in regs->flags. The pending op pointer is always in DX independent of the build mode (32/64-bit) to make the pending op pointer retrieval uniform. The size of the pointer is stored in the matching criticial section range struct and the core code retrieves it from there. So the pointer retrieval function does not have to care. It is bit-size independent: return regs->flags & X86_EFLAGS_ZF ? regs->dx : NULL; There are two entry points to handle the different robust list pending op pointer size: __vdso_futex_robust_list64_try_unlock() __vdso_futex_robust_list32_try_unlock() The 32-bit VDSO provides only __vdso_futex_robust_list32_try_unlock(). The 64-bit VDSO provides always __vdso_futex_robust_list64_try_unlock() and when COMPAT is enabled also the list32 variant, which is required to support multi-size robust list pointers used by gaming emulators. The unlock function is inspired by an idea from Mathieu Desnoyers. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Acked-by: Uros Bizjak Link: https://lore.kernel.org/20260311185409.1988269-1-mathieu.desnoyers@efficios.com Link: https://patch.msgid.link/20260602090535.883796247@kernel.org

x86/vdso: Prepare for robust futex unlock support

2026-06-03T09:38:52Z

There will be a VDSO function to unlock non-contended robust futexes in user space. The unlock sequence is racy vs. clearing the list_pending_op pointer in the task's robust list head. To plug this race the kernel needs to know the critical section window so it can clear the pointer when the task is interrupted within that race window. The window is determined by labels in the inline assembly. Add these symbols to the vdso2c generator and use them in the VDSO VMA code to update the critical section addresses in mm_struct::futex on (re)map(). The symbols are not exported to user space, but available in the debug version of the vDSO. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://patch.msgid.link/20260602090535.828312645@kernel.org

x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags'

2026-05-27T22:20:06Z

Now that the minimum supported version of LLVM for building the kernel has been raised to 17.0.1, the inclusion condition added by 3e30278e0c71 ("x86/entry/vdso32: Omit '.cfi_offset eflags' for LLVM < 16") will always be true. Revert the change to clean up the source code. Acked-by: H. Peter Anvin (Intel) Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-13-b3b8cda46bdd@kernel.org Signed-off-by: Nathan Chancellor

x86/vdso: Fix incorrect size in munmap() on map_vdso() failure

2026-05-19T14:36:34Z

In map_vdso(), if a failure occurs during the installation of the VVAR mappings, the error path attempts to clean up previously allocated mappings using do_munmap(). However, the cleanup for the VVAR mapping is incorrectly using image->size (the size of the vDSO text) instead of the actual size allocated for the VVAR area. Replace the incorrect do_munmap() image->size parameter with the constant VDSO_NR_PAGES * PAGE_SIZE. Ensure the unmap size exactly matches the size used during the vdso_install_vvar_mapping() phase to provide a symmetrical and complete teardown of the memory region. Fixes: e93d2521b27f ("x86/vdso: Split virtual clock pages into dedicated mapping") Signed-off-by: Guilherme Giacomo Simoes Signed-off-by: Thomas Gleixner Reviewed-by: Thomas Weißschuh Link: https://patch.msgid.link/20260503191609.551817-1-trintaeoitogc@gmail.com

Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-15T19:59:16Z

Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ...

Merge tag 'x86-vdso-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T21:16:27Z

Pull x86 vdso updates from Ingo Molnar: "vdso cleanups by Thomas Weißschuh: - Clean up remnants of VDSO32_NOTE_MASK - Drop pointless #ifdeffery in vvar_vclock_fault()" * tag 'x86-vdso-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vdso: Drop pointless #ifdeffery in vvar_vclock_fault() x86/vdso: Clean up remnants of VDSO32_NOTE_MASK

Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T17:53:44Z

Pull vdso updates from Thomas Gleixner: - Make the handling of compat functions consistent and more robust - Rework the underlying data store so that it is dynamically allocated, which allows the conversion of the last holdout SPARC64 to the generic VDSO implementation - Rework the SPARC64 VDSO to utilize the generic implementation - Mop up the left overs of the non-generic VDSO support in the core code - Expand the VDSO selftest and make them more robust - Allow time namespaces to be enabled independently of the generic VDSO support, which was not possible before due to SPARC64 not using it - Various cleanups and improvements in the related code * tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits) timens: Use task_lock guard in timens_get*() timens: Use mutex guard in proc_timens_set_offset() timens: Simplify some calls to put_time_ns() timens: Add a __free() wrapper for put_time_ns() timens: Remove dependency on the vDSO vdso/timens: Move functions to new file selftests: vDSO: vdso_test_correctness: Add a test for time() selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c selftests: vDSO: vdso_test_correctness: Handle different tv_usec types selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers" random: vDSO: Remove ifdeffery random: vDSO: Trim vDSO includes vdso/datapage: Trim down unnecessary includes vdso/datapage: Remove inclusion of gettimeofday.h vdso/helpers: Explicitly include vdso/processor.h vdso/gettimeofday: Add explicit includes random: vDSO: Add explicit includes MIPS: vdso: Explicitly include asm/vdso/vdso.h ...