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5 daysMerge tag 'mm-nonmm-stable-2026-10-25-14-57' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - "ocfs2: exit recovery thread on mount error path" (Joseph Qi): Stop OCFS2 recovery before freeing failed-mount state and replay slots, closing use-after-free and double-free races. Defer suballocator reclaim to break a transaction-lock deadlock with dismount. - "ocfs2: validate suballoc slot and bit of metadata blocks" (Joseph Qi): Validate OCFS2 metadata suballocator slots, bits and directory index block locations. Reject corrupt metadata with filesystem errors instead of BUGs or out-of-bounds accesses. - "ocfs2: deal with legacy signed name hash values" (Joseph Qi): Restore OCFS2 lookups for non-ASCII names stored with legacy signed hashes. Use stored xattr hashes during bucket splits to avoid duplicate entries and spurious ENOSPC failures. - "ocfs2: stabilize dentry names in file and setattr traces" (Cen Zhang): Snapshot OCFS2 names during file and setattr tracing to prevent rename races using freed storage or mismatched names and lengths. Preserve trace formats and the locked release open-count sample. - "panic: fix panic_force_cpu= redirect races and NMI bypass" (Bradley Morgan): Fix panic_force_cpu races and NMI redirection so crash-kernel CPU selection is honored. Preserve variable arguments on failed redirects and use a static message buffer. - "fat: allocate multiple clusters in fallocate" (Matheus Alves de Almeida): Allocate FAT clusters in batches for FALLOC_FL_KEEP_SIZE and batch FAT updates. This removes repeated single-cluster allocation overhead, particularly on synchronous mounts. - "scripts/gdb: fix radix tree lookup and stack depot diagnostic" (Ting-Han Hou): Fix GDB radix-tree lookup and its handling of XArray sibling, retry and zero entries. Also repair the stack-depot diagnostic for an out-of-range pool index. - "hung_task: Improve warning budget handling and task reporting" (Aaron Tomlin): Reset the hung-task warning budget after recovery so later hangs remain visible. Keep the configured limit intact and emit one summary per scan when detailed reports exhaust the budget. - "bootconfig: Reject unexpected data after null character and cleanups" (Masami Hiramatsu): Reject bootconfig data after an embedded null while accepting trailing padding. Validate the full input in the userspace tool, and retain internal tree sanity checks there rather than in the kernel. - "kbuild: GCOV cleanups following the prefer-atomic fix" (Konstantin Khorenko): Use the actual GCOV build flags in the prefer-atomic compiler probe. Move flag setup into scripts/Makefile.gcov and skip the probe when GCOV is disabled. - "ocfs2: xattr bucket validation fixes" (Joseph Qi): Accept valid OCFS2 xattr buckets spanning 512-byte blocks, avoiding false read-only remounts. Reject misaligned buckets and return errors instead of panicking on corrupt defrag metadata. - "ocfs2: fix metadata reservation for xattr value trees" (Joseph Qi): Reserve enough OCFS2 metadata for new and relocated xattr value trees. Fix shortfalls which could cause ENOSPC, dropped entries and leaked clusters on fragmented filesystems; remove duplicate reservations. - "Introduce arch_do_panic" (Mete Durlu): Add arch_do_panic() and move s390 and sparc handling out of generic panic code. The architecture-specific actions now follow the end-of-panic marker. - "checkpatch: userspace improvements" (Petr Vorel): Improve checkpatch's userspace detection and suppress kernel-only checks. Recognize standard inttypes macros and add explicit --userspace and --no-userspace overrides. - "ocfs2: validate dr_fs_generation of dir index root blocks" (Joseph Qi): Check OCFS2 directory index generations and leaf block numbers. Reject stale or misplaced blocks instead of using metadata left by a previously formatted filesystem. - "selftests/membarrier: Skip an unregistered memory barrier test on Musl" (Chris Gellermann): Skip the unregistered membarrier test when libc has already registered the command. Musl does this during thread creation, causing false failures in the multithreaded test. - "init: fix array boundary bugs in boot parameter parsing" (Wilson Felipe Pereira): Fix boot argument boundary cases which leave stale arguments in init's command line or panic when replacing the final environment variable. Clear the last slot and check duplicates before the limit. Summary of the 87 singletons in this merge: The OCFS2 singletons fix deadlocks between xattr updates and inline truncation, and during inode reclaim. Corrupt quota and extent metadata could also crash the kernel or corrupt memory; these paths now check the layout before using it. Other fixes close use-after-free and publication races around cluster reconfiguration, node failure, quota remount errors and shared refcount trees. New files now retain security labels from all stacked LSMs instead of silently dropping all but one. Valid xattr insertions also stop tripping FORTIFY on builds with counted arrays. Elsewhere, a lost wakeup could leave hardware-monitoring reads stuck in unkillable sleep and block further I2C traffic. That is fixed, as are kernel memory leaks in POSIX message-queue notifications and tmpfs casefold setup which could grow until memory is exhausted. A driver removal race which could crash the kernel is fixed too. The hibernation command through reboot() also stops taking the same mutex twice, avoiding a deadlock before suspension. On the boot side, bzip2 decoding now accepts valid full blocks emitted by lbzip2, fixing failures to boot those compressed kernels. Malformed bzip2 streams can no longer overflow the decode buffer, and LZ4 initrds are checked before the decoder can read past their end. FAT rejects geometry which overflows the data-area calculation on 32-bit systems, and rolls back entries when inode setup fails, preventing failed creations from reappearing after remount. The x86 XOR and RAID6 AVX paths also avoid imposing a slowdown on subsequent SSE code. * tag 'mm-nonmm-stable-2026-10-25-14-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (134 commits) scripts/gdb: fix stack depot out-of-bounds diagnostic scripts/gdb: fix radix tree lookup pointer handling ocfs2/cluster: remove zero-address nodes from IP tree on teardown ocfs2: snapshot the dentry name while tracing file release ocfs2: snapshot dentry names in file and setattr traces ocfs2/dlm: drain join handlers before releasing module text MAINTAINERS: update Markus's e-mail address mailmap: add entries for Andrew Jones stackdepot: stop preallocating after the final pool ocfs2: drain quorum work before removing the cluster watchdog: force console verbose when reporting lockups profiling: fix sampling step on 64-bit big-endian systems kernel/reboot: avoid potential deadlocks during suspension compat: avoid double rounding in times() ocfs2: pin owning modules for open debugfs files ocfs2/cluster: initialize heartbeat regions before publishing them selftests/proc: proc-pid-vm: fix unused variable warning on non-x86 ocfs2: pin refcount trees before dropping the lookup lock ocfs2: validate the xattr tree root of an indexed xattr block ocfs2/dlm: hold the lookup reference across convert AST enqueue ...
9 daysMerge tag 'mm-stable-2026-10-19-21-33' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - "selftests/mm: improve khugepaged coverage" (Kiryl Shutsemau): Give khugepaged a proper workout. Extend the tests to all supported mTHP orders, check exactly which windows collapsed, and make scan completion deterministic. Race collapse against faults, pinning, fork and remap; verify that the contents survive. Add coverage for whole-page-table zaps and memory pressure too. - "selftests/mm: separate GUP microbenchmarking from functional testing" (Sarthak Sharma): Untangle GUP benchmarking from correctness testing. Move the benchmark into tools/mm, add a standalone harness-based GUP selftest, and move shared helpers into tools/lib/mm. Give each tool one job instead of mixing timing measurements with correctness checks. Cover the mapping, pinning and batch-size combinations explicitly. - "mm: Switch device DAX to section-based vmemmap optimization" (Muchun Song): Apply section-based vmemmap optimization to device DAX. Rework the backing metadata layout to save memory while preserving the handling of device memory hotplug and its different alignment and lifetime requirements. - "mm: Introduce section-based vmemmap optimization for HugeTLB" (Muchun Song): Cut the memory consumed by HugeTLB's struct page array with section-based vmemmap optimization. Arrange the metadata so large huge pages need fewer backing pages, while keeping initialization, teardown and the various hugepage configurations straight. - "mm/huge_memory: clean up and decouple the anon and file split helpers" (Kairui Song): Separate anonymous and file-backed folio splitting, which have rather different locking and bookkeeping requirements. Move the work into separate helpers, drop dead checks and tidy swap-cache handling. Fix error paths, including one that could leave a folio frozen. Keep the swap cache cases separate from file-cache splitting. - "mm: Unconditional per-VMA locks and cleanups" (Dave Hansen): Make per-VMA locking unconditional and clean up the old conditional code around it. This removes configuration-dependent plumbing and lets callers depend on one locking model rather than carrying both cases along. - "memcg: remove the v1 soft limit" (Shakeel Butt): Remove the old cgroup v1 memory soft-limit machinery. This has long since been superseded by the newer memory-control interfaces; hauling around a separate reclaim scheme for it no longer buys us much. - "read proc/pid/smaps_rollup under per-vma lock" (Suren Baghdasaryan): Read /proc/PID/smaps_rollup using per-VMA locks where possible, rather than holding mmap_lock across the entire walk. Retain the contention fallback and add tearing tests. This considerably reduces latency when another thread is busy changing its mappings. - "mm/damon: introduce data access-as-a-data attribute" (SJ Park): Teach DAMON to expose memory access observations as data attributes, making them available to the probe and filtering machinery. Extend the interfaces, documentation and tests so the new information can be used rather than merely collected. - "Remove PG_private by using page/folio->private checks instead" (Zi Yan): Get rid of PG_private and use the folio's private pointer to say whether private data is attached. Convert the filesystem users, including erofs, f2fs and md, and clean up the old accessors and flags. There are a few special cases, notably swapcache and hugetlb, which need explicit care. - "mm: make userland page table freeing RCU-safe" (Lorenzo Stoakes): Make freeing userspace page tables safe against RCU readers. Sort out the page-table lifetime and locking rules so walkers cannot stumble over freed tables while mappings are being torn down. - "make unused huge shrinker memcg aware" (Qi Zheng): Make shmem's unused-huge-folio shrinker aware of memory cgroups, so reclaim can find those folios under the right memcg. Wire up the per-memcg tracking and its lifetime rules, and give the shrinklist its own lockdep class to avoid spurious dependency reports. - "mm: Drop pxd_ERROR()" (Anshuman Khandual): Remove the old pxd_ERROR() page-table checks and their architecture-specific baggage. Simplify the common page-table interfaces and callers now that these checks no longer serve a useful purpose. - "memcg: group struct fields by access pattern" (Shakeel Butt): Rearrange memcg's hot and cold fields according to how they're actually accessed. Keep frequently updated counters and their neighboring state from fighting over cachelines and reduce needless cacheline traffic. - "mm/damon/core: fix the size charged for a filter-trimmed region" (Donggeun Yoo): Fix DAMOS quota accounting when a filter trims a monitoring region. Charge only the part left after filtering, not the original region, and add KUnit coverage. Previously the excluded memory could eat into the quota and make schemes run more slowly than requested. - "mm/damon: add kunit and selftests for probes and probe weights" (SJ Park): Add more tests for DAMON probes and their weights, including validation and the results reported to userspace. This is mostly about catching regressions in the newer probe infrastructure before they become harder to diagnose. - "mm: memcontrol: constify the read side of the read side of the memcg API" (Tal Zussman): Mark the read-only parts of the memcg interface const, from folio and lruvec accessors to counters and swap helpers. Most of this is mechanical, but it makes the contracts clearer and lets the compiler catch accidental writes. - "mm/damon/vaddr: support {prep,apply}_probes" (SJ Park): Support the new prepare/apply probe operations in DAMON's virtual-address backend. This brings vaddr monitoring into line with the probe infrastructure and makes the added probe types useful there too. - "mm/mglru: clean up folio counters and flag usage" (Kairui Song): Simplify MGLRU's folio counters and flag handling. Remove redundant accounting paths and make the state transitions easier to follow without changing the intended reclaim policy. - "arch, mm/execmem: resolve confusion about set_direct_map_valid_noflush()" (Mike Rapoport (Microsoft)): Clarify and straighten out the set_direct_map_valid_noflush() interface across architectures and execmem. Make the requested mapping changes and the callers' expectations agree, rather than relying on subtly different architecture behavior. - "mm: zswap: free cold writeback folios promptly" (Alexandre Ghiti): Free zswap writeback folios as soon as their disk write completes. They are cold temporary buffers, so putting them on the LRU only makes reclaim rediscover them later. Extend swap-cache dropbehind and let zswap keep these folios off the LRU altogether. - "mm: gup: cleanup gup_fast call chain" (Aristeu Rozanski): Clean up the GUP-fast call chain and simplify how the fast-path helpers pass their arguments and results around. Keep the page-pin behavior the same while making the call sequence easier to maintain. - "mm: optimize zone-device memmap initialization" (Li Zhe): Speed up initialization of zone-device struct pages. Avoid redundant work when setting up large device-memory ranges, where touching every descriptor can get expensive. - "mm/zswap: shrink zswap_entry via a pool id" (Jianyue Wu): Reduce the size of zswap_entry by storing a compact pool identifier instead of a full pointer. Keep the pool lookup and lifetime handling correct while saving per-entry metadata. - "mm/damon: support access monitoring of hugetlb-backed memory" (Krishna Iyer): Let DAMON monitor hugetlb-backed memory too. Extend the relevant access checks and add coverage so those mappings no longer fall through a hole in the monitoring machinery. - "mm/execmem: fixes and cleanups for the ROX cache" (Mike Rapoport): Tidy execmem's read-only-executable cache and fix its handling of the awkward allocation and release cases. The aim is to make the cache's ownership and permission transitions more predictable. - "zsmallc: remove old object read API" (Sergey Senozhatsky): Drop zsmalloc's old object-read API and move its remaining users to the supported access mechanism. This removes a duplicate interface which we no longer need. - "mm/mempolicy: stop copying state in the interleave paths" (Gregory Price): Stop copying mempolicy state in the interleave paths when a reference to the existing policy will do. This avoids extra work and makes the ownership rules less obscure. - "mm/mglru: speed up inc_min_seq() and fix cold/hot inversions" (Barry Song): Make MGLRU's generation advancement cheaper and fix cases where cold and hot folios end up in the wrong order. Adjust the counter and list handling so reclaim doesn't keep passing over the better eviction candidates. - "mm: Fix MF_DELAYED handling on memory failure" (Lisa Wang): Treat MF_DELAYED as a partially completed memory-failure operation, not an outright failure. Propagate that result correctly through shmem and the generic handler, fix the extra-reference accounting, and add tests for the resulting SIGBUS behavior. - "tools/mm/page_owner_sort: fix --sort, add module filter, improve usage" (Ye Liu): Fix page_owner_sort's --sort handling, add module-based filtering and make the usage output more helpful. This makes the tool less frustrating when tracking down who is holding on to pages. - "mm/damon: move damos filter range arguments validation to core" (SJ Park): Move DAMOS filter range validation into the core, where all callers can share it. Also close the sysfs read-twice races which could pass inconsistent ranges, and add tests for invalid input. - "mm/damon: misc cleanups" (Zenghui Yu): Clean up a collection of small DAMON rough edges in the core, interfaces and tests. No large behavior change here, just simpler code and fewer opportunities for confusion. - "mm/damon: cleanup code, add test cases, and update guidances in docs" (SJ Park): Clean up DAMON's core and interfaces, add missing test cases and bring the documentation into line with the code. These changes should make the newer facilities easier to understand and maintain. - "mm/damon: introduce hugepage_size probe filter" (SJ Park): Add a DAMON probe filter for hugepage size. Let users select a range of folio sizes through sysfs, validate the range and document the new interface, so monitoring can concentrate on memory backed by the desired hugepage sizes. - "selftests/mm: pagemap_ioctl test fixes and cleanups" (Zenghui Yu): Fix some pagemap ioctl test assumptions and clean up their setup and reporting. Make failures point to the operation that went wrong rather than to test harness bookkeeping. - "mm: avoid large folio splits when swap is unavailable" (Johannes Weiner): Avoid splitting large folios merely to attempt swap when no swap space is available. There is little point paying for an expensive split when reclaim cannot actually swap the resulting pages out. - "mm: workingset: fix the shadow node budget under MGLRU" (Hui Zhu): Fix the workingset shadow-node budget with MGLRU enabled. Keep the shadow entries within the intended limits so refault tracking does not quietly consume more metadata than it should. - "selftests/mm: TAP output and global-state fixes" (Song Hu): Fix selftests which produce misleading TAP output or fail to restore global settings after a run. A test ought to leave the system as it found it, particularly when a whole suite follows behind. - "mm: remove page_swap_entry()" (Tal Zussman): Remove page_swap_entry() and convert its remaining users to the folio and swap-entry helpers. Lose an old page-level interface and make the swap paths a little more consistent. - "mm: refactor zonelist constructors and iterators" (Gregory Price): Refactor the zonelist construction and walk helpers to reduce duplicated logic. Keep the allocation ordering rules intact while making it clearer how zones are selected. - "mm: kmemleak: batch the struct page scan" (Breno Leitao): Scan adjacent struct pages in batches instead of taking kmemleak_lock once for every single page. This preserves scan coverage and the lock-hold bound, while cutting overhead substantially on debug kernels. - "mm/damon: misc improvements in tests and documents" (Zenghui Yu): Fix some DAMON selftests which leave kdamond running or fail under Python safe-path mode, and improve the KUnit coverage and documentation. Nothing especially glamorous, but these are worth doing. - "mm/damon: introduce probe_hits_wsum DAMOS core filter" (SJ Park): Add a DAMOS core filter using weighted probe-hit counts. This gives schemes another way to select regions based on what the monitoring probes observed. - "mm/mglru: fix ineffective memory protection for non-kswapd reclaim" (Ridong Chen): Fix MGLRU's memory protection handling for reclaim outside kswapd. The protection settings weren't having the intended effect in these paths, leaving protected memory more exposed than requested. - "mm/damon: improve readability, clarity and test coverage" (SJ Park): Simplify a handful of DAMON core helpers, clarify their behavior and expand test coverage. There are no intended userspace-visible changes in this batch. - "mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func()" (Kefeng Wang): Stop identifying reclaim and compaction workers through the PF_KSWAPD and PF_KCOMPACTD task flags. Use their kthread functions instead and remove the redundant flag plumbing. - "mm/hugetlb: fix surplus accounting and availability checks during demotion" (Longlong Xia): Fix HugeTLB surplus accounting and availability checks when demoting huge pages. Keep the counters and reservation decisions consistent as one huge page turns into several smaller ones. - "mm/damon: add kunit tests for probe_hits handling and probe params validation" (Jason Angelov): Add KUnit tests for DAMON probe-hit handling and invalid probe parameters. These cover edge cases that were too easy to miss in ordinary monitoring tests. - "mm/damon: fix misc bugs in kunit, quota goals and sysfs refresh_ms" (SJ Park): Fix a few DAMON bugs in KUnit tests, quota-goal handling and the sysfs refresh interval. Small fixes, but the incorrect results and control behavior were real. - "mm: zswap: optimize zswap invalidate and store" (Kefeng Wang): Simplify zswap's invalidate and store paths to avoid avoidable lookups and work. Keep the entry lifetime rules intact while making those frequent operations cheaper. - "mm: replace custom ratelimiting logic" (Pedro Falcato): Replace hand-rolled MM rate limiting with the common kernel helpers. There is no need to maintain another local version of the same mechanism. - "mm/vmalloc: minor cleanups" (Ye Liu): Tidy some vmalloc initialization and reporting code, and pull duplicated vmap-area insertion work into a helper. No functional changes are intended. - "mm/mglru: clean up isolate_folios for readability and clarity" (Ridong Chen): Clean up MGLRU's isolate_folios() so the decisions are easier to read and verify. Keep reclaim behavior unchanged while removing unnecessary twists in the control flow. - "Catch automatic storage in IDA and Maple Tree definitions" (Yury Norov): Catch IDA and maple-tree definitions placed in automatic storage where the lifetime rules are wrong or easy to get wrong. Add checks so such mistakes are harder to slip through unnoticed. - "mm, swap: some random fixes and cleanups" (Kemeng Shi): Fix and simplify a few unrelated swap paths, removing redundant work and tidying up error handling. A small collection of things which were better fixed than left lying around. - "mm/page_io: folio conversion cleanups" (Tal Zussman): Finish some page-to-folio conversions in swap I/O, removing obsolete wrappers and using folio operations consistently. The I/O behavior is intended to remain the same. - "mm/swap: skip empty clusters in the swapoff scan" (Youngjun Park): Skip empty swap clusters during swapoff instead of walking slots which have nothing to release. This avoids pointless work on sparsely used swap devices. - "mm: trace: decode architecture-specific VMA flags" (Meijing Zhao): Teach the VMA trace output to decode architecture-specific flags, rather than leaving them as unexplained bits. That should make tracing a good deal more useful when debugging unusual mappings. - "mm, swap: don't spin on a bad swap entry" (Breno Leitao): Stop repeatedly retrying a swap entry which is already known to be bad. Make the error path terminate cleanly instead of wasting CPU chasing an entry that cannot be used. - "mm/page_isolation: fix UBSAN shift-out-of-bounds in isolate_single_pageblock" (Qi Xi): Fix an out-of-range shift in isolate_single_pageblock() and tighten its associated boundary handling. UBSAN found the issue; the result should be more robust pageblock isolation. - "mm: khugepaged: fix tracepoint UAF" (Vernon Yang): Fix a use-after-free in khugepaged tracepoint handling. Make sure the information recorded by tracing stays valid for as long as the trace event needs it. - "mm/damon: fix DAMOS bugs in core, paddr and vaddr" (SJ Park): Fix several DAMOS problems across the core and physical- and virtual-address backends. The changes close error cases and bring the implementations back into agreement. - "mm/hugetlb_cgroup: move the per-node usage along with the folio" (Hongfu Li): Move HugeTLB per-node usage accounting when folios migrate between nodes or are reparented to another cgroup. Otherwise numa_stat can retain stale charges and even underflow when the folio is freed. - "docs/core-api: memory-allocation: add k[mz]alloc_obj() and clarify kmalloc" (Mike Rapoport): Document the typed k[mz]alloc_obj() allocation helpers and clear up some kmalloc guidance. Make it easier for callers to choose the right interface. - "selftests/mm: Validate selections and scope memfd_secret setup" (Tianyi Chen): Check selftest selections before running and confine memfd_secret setup to the cases that actually need it. Avoid confusing failures caused by the test harness itself. - "mm/damon: move zero damos quota target_value handling to the core layer" (SJ Park): Handle a zero DAMOS quota goal target in the core rather than making each user of the interface invent its own rule. Keep quota decisions consistent across callers. - "mm/damon: Introduce a huge page collapsing mechanism using auto tuning" (Asier Gutierrez): Add an auto-tuned DAMON mechanism for collapsing huge pages. Use monitoring feedback to decide when collapse is worthwhile rather than forcing one fixed policy onto every workload. - "kmemleak: fix stale documentation and raise the verbose default" (Breno Leitao): Bring the kmemleak documentation up to date and require a third confirming scan before verbose kernels print a suspected leak. The extra scan helps suppress transient false positives in noisy debug builds. - "mm/memory: improve insert_pages() error handling" (Avi Weiss): Tighten insert_pages() error handling so partial failures are reported and cleaned up consistently. The caller should not have to guess how far the operation got. - "mm/damon: allow NULL or unstarted damon_ctx parameter for damon_call()" (SJ Park): Make damon_call() handle NULL and not-yet-started contexts safely. Simplify the rules for callers and avoid an indefinite wait on an invalid state. - "mm/damon: introduce pgidle_set probe filter type" (SJ Park): Add a pgidle_set DAMON probe filter, giving monitoring users another way to select pages by their idle-tracking state. Wire it through the filter interfaces and tests. - "mm/damon/core: remove unused helper functions" (Cheng-Han Wu): Remove DAMON core helpers which no longer have callers. Keep the API surface smaller rather than retaining dead code just in case. - "mm: stop calling pmd_folio() on special PMDs" (Gregory Price): Avoid calling pmd_folio() on special PMD mappings that have no struct page. The old assumption could fault in procfs walkers; use the normal-folio checks and handle those mappings properly. - "mm: remove three unused helpers from mm.h" (Tal Zussman): Remove three unused helpers from mm.h. Fewer obsolete interfaces for the next person to stumble over. - "mm/damon: improvements in efficiency, error handling, documents" (Liew Rui Yan): Skip needless DAMOS quota work once the quota is full, propagate a missing sysfs error and tidy a couple of comments. The ignored error could make a monitoring-start request appear successful when it wasn't. - "docs/mm/damon/design: add explanation of nr_snapshots" (Liew Rui Yan): Explain DAMON's nr_snapshots accounting in the design documentation and straighten out the associated terminology. Make it clearer what users should expect from that counter. - "selftests/cgroup: fixes for test_zswap on single core VM" (Wilson Felipe Pereira): Fix two test_zswap failures on single-CPU VMs. Wait for the exiting child's cgroup to become unpopulated before reconfiguring it, and avoid another test assumption which breaks under constrained scheduling. - "docs/ksm: fix advisor documentation and comment" (Jinjiang Tu): Correct the KSM advisor documentation and a misleading code comment. Keep the description aligned with how the advisor actually works. - "Fix bugs in HugeTLB allocation when mem_cgroup_charge_hugetlb() fails" (Ackerley Tng): Fix HugeTLB allocation cleanup when the memcg charge fails. Make sure failure exits undo what was allocated rather than leaving stale accounting or resources behind. - "mm, memcg: fix memory.peak reset clobbering other fds' watermark" (Ridong Chen): Fix memory.peak reset handling so resetting one file descriptor doesn't overwrite the watermark kept for another. Keep those per-open measurements independent as intended. - "mm: reject zone device folios in more folio walkers" (Gregory Price): Reject zone-device folios in page walkers that cannot safely handle them. Extend the existing checks rather than assuming every folio has ordinary system-memory backing. - "percpu: remove code with no effect" (Sang-Heon Jeon): Remove a few pieces of percpu code which no longer do anything. There is no reason to keep maintaining dead paths. * tag 'mm-stable-2026-10-19-21-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (539 commits) mm: shmem: assign a lock class to the unused huge shrinklist mm: vmscan: put rotation-missed folios at the LRU tail mm: kmemleak: scan the struct page array in MAX_SCAN_SIZE batches mm: kmemleak: move the struct page scan into a helper mm/damon: document that a zero sample_interval is accepted mm/damon: fix typos in comments mm/damon/sysfs: propagate damon_call() error in turn_damon_on mm/damon/core: skip quota score setup when the quota is full mm/damon/tests/core-kunit: test the size charged for a filter-trimmed region mm/damon/core: charge only the part of a region the filter left mm: disallow raw PFN mappings of huge/shared zeropage selftests/mm: zap whole PTE tables in the khugepaged race harness selftests/mm: add memory-pressure threads to the khugepaged race harness selftests/mm: race the collapse of windows with holes selftests/mm: add khugepaged race harness selftests/mm: check that one khugepaged pass collapses one window selftests/mm: run every supported collapse order by default selftests/mm: cover a shared-source collapse write race selftests/mm: parameterize the mixed-source collapse case by source order selftests/mm: add order-parameterized khugepaged collapse cases ...
2026-10-08mm: userland pgtable freeing is RCU-safe now, remove leftover bitsLorenzo Stoakes (ARM)
Now every architecture has been converted to support CONFIG_MMU_GATHER_RCU_TABLE_FREE, this configuration option no longer makes any sense to keep around. Therefore remove it, and remove all the dead code that existed for !CONFIG_MMU_GATHER_RCU_TABLE_FREE architectures previously. Additionally, CONFIG_MMU_GATHER_TABLE_FREE is no longer necessary, as all architectures instead use CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE when a custom __tlb_remove_table() is required, so remove this too. A number of architectures only enabled CONFIG_MMU_GATHER_RCU_TABLE_FREE if CONFIG_MMU was set, however the mmu_gather logic only actually does something meaningful if CONFIG_MMU is set (mmu_gather.c is only compiled in this case, for instance). As a result, there's no need to gate any of this logic on CONFIG_MMU explicitly. CONFIG_PT_RECLAIM however does have a strict dependency on CONFIG_MMU, so make this dependency explicit. Additionally, correct comments to remove references to non-RCU page table gathering and make it clear that this is not 'semi-RCU', nor has it been since commit 1fb3d8c20bfa ("mm/mmu_gather: replace IPI with synchronize_rcu() when batch allocation fails"). With this change in place the kernel policy is now that userspace page tables are freed after an RCU grace period, and thus it is now safe to unconditionally perform page table walks under RCU, safe in the knowledge that page tables will not be freed underneath the walker. This is all that is guaranteed, however, so naturally it is still incumbent upon page table walkers to ensure that the page table entries are as expected. Link: https://lore.kernel.org/20260925-rcu-pagetable-freeing-v5-11-31e91065fea4@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Kiryl Shutsemau (Meta) <kas@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Nico Pache <nico.pache@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Barry Song <baohua@kernel.org> Cc: Usama Arif <usama.arif@linux.dev> Cc: Guo Ren <guoren@kernel.org> Cc: Brian Cain <bcain@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Simon Schuster <schuster.simon@siemens-energy.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Stafford Horne <shorne@gmail.com> Cc: Rich Felker <dalias@libc.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Paul Walmsley <pjw@kernel.org> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: James Bottomley <james.bottomley@hansenpartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Christophe Leroy <chleroy@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Thomas Gleixner <tglx@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Qi Zheng <qi.zheng@linux.dev>
2026-10-06arch/Kconfig: fix dead conditions by removing dead optionsJulian Braha
These two 'int' options: ARCH_MMAP_RND_BITS_DEFAULT ARCH_MMAP_RND_COMPAT_BITS_DEFAULT are used directly as conditions for defaults. 'int' options should not be used as conditions, because they will always evaluate to false. Let's remove these options, because they are not used anywhere else. This dead code was found by kconfirm, a static analysis tool for Kconfig. Link: https://lore.kernel.org/20260830230016.2730093-1-julianbraha@gmail.com Signed-off-by: Julian Braha <julianbraha@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
2026-09-02sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY}Mark Rutland
PREEMPT_DYNAMIC is now limited to the FULL and LAZY preemption models. Switching model only changes the behaviour of dynamic_preempt_lazy(), which uses a static key. There are no other static calls or static keys, and so there's no need for HAVE_PREEMPT_DYNAMIC_CALL or HAVE_PREEMPT_DYNAMIC_KEY. The static key used by dynamic_preempt_lazy() is entirely local to kernel/sched/core.c, and any architecture which selects ARCH_HAS_PREEMPT_LAZY implements the necessary support. Remove PREEMPT_DYNAMIC's dependencies on HAVE_PREEMPT_DYNAMIC_CALL and HAVE_PREEMPT_DYNAMIC_KEY entirely, leaving the dependency on ARCH_HAS_PREEMPT_LAZY. For architectures which previously selected HAVE_PREEMPT_DYNAMIC_KEY, PREEMPT_DYNAMIC will now be selected by default, matching x86. As the runtime impact is limited to dynamic_preempt_lazy(), this shouldn't be as concerning as previously (e.g. where calls to {cond,might}_resched() stubs could introduce a measurable penalty). As all of this can work without jump labels, JUMP_LABEL is not selected explicitly. It is obviously preferable to have JUMP_LABEL enabled, but this is not functionally necessary. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com> Tested-by: Mete Durlu <meted@linux.ibm.com> Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com> Tested-by: Jinjie Ruan <ruanjinjie@huawei.com> Link: https://patch.msgid.link/20260803191731.3244294-6-mark.rutland@arm.com
2026-08-18Merge tag 'timers-vdso-2026-08-17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull VDSO updates from Thomas Gleixner: - Consolidate the VDSO datastore further and provide support for mlock_all() and prefaulting. - Provide 32-bit legacy time related functionality only if CONFIG_COMPAT_32BIT_TIME is enabled. The config switch exists, but architecture code still exposes the legacy functionality even disabled. Clean this up by adding the missing guards and validating at build time that the VDSO is legacy free if disabled. - Consolidate the VDSO related config options in core and drivers, which removes some non-sensical dependencies and quite an amount of #ifdeffery. - Clean up the PAGE_SIZE definition maze * tag 'timers-vdso-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) random: vDSO: Drop custom PAGE_SIZE definitions LoongArch: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery clocksource/drivers/timer-riscv: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery clocksource/drivers/arm_arch_timer: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery clocksource/drivers/mips-gic-timer: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery MIPS: csrc-r4k: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery vDSO: Make clockmode constants available without CONFIG_GENERIC_GETTIMEOFDAY kbuild: Support generated asm-headers in subdirectories vdso: Rename HAVE_GENERIC_VDSO to VDSO_DATASTORE vdso: Drop HAVE_GENERIC_VDSO from architecture kconfig files vdso: Automatically select HAVE_GENERIC_VDSO if necessary MIPS: vdso: Stop using CONFIG_HAVE_GENERIC_VDSO vdso: Remove the dependency on HAVE_GENERIC_VDSO from ARCH_HAS_VDSO_ARCH_DATA futex: Remove dependency on HAVE_GENERIC_VDSO from FUTEX_ROBUST_UNLOCK vdso/gettimeofday: Verify COMPAT_32BIT_TIME interactions sparc: vdso: Respect COMPAT_32BIT_TIME MIPS: VDSO: Respect COMPAT_32BIT_TIME powerpc/vdso: Respect COMPAT_32BIT_TIME ARM: VDSO: Respect COMPAT_32BIT_TIME arm64: vdso32: Respect COMPAT_32BIT_TIME ...
2026-08-18Merge tag 'timers-cleanups-2026-08-17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull treewide timer related cleanups from Thomas Gleixner: - Remove the leftover CLOCK_TICK_RATE which has been scheduled for removal more than a decade ago along with some now empty asm/timex.h files. - Consolidate delay timer calibration The construct of having a define in a header requires that architectures provided asm/timex.h for no reason. Also the function name for reading the delay timer is confusing at best. Use a config switch to enable that functionality and rename the function to delay_read_timer() to make the purpose clear. This removes some more now empty asm/timex.h files as well. * tag 'timers-cleanups-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: calibrate: Rework delay timer calibration treewide: Remove CLOCK_TICK_RATE x86: Use PIT_TICK_RATE instead of CLOCK_TICK_RATE
2026-07-15calibrate: Rework delay timer calibrationThomas Gleixner
The header define in asm/timex,h and the naming of the function to read the delay timer are confusing at best. Convert it to a config switch selected by the archictures which provide the functionality and rename the function to delay_read_timer(), which makes the purpose clear. Move the declaration to linux/delay.h where it belongs. Remove the resulting empty asm/timex.h files as well. No functional change. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260410120317.978403520@kernel.org
2026-07-15vdso: Remove the dependency on HAVE_GENERIC_VDSO from ARCH_HAS_VDSO_ARCH_DATAThomas Weißschuh
Align ARCH_HAS_VDSO_ARCH_DATA with ARCH_HAS_VDSO_TIME_DATA, making it selectable even without HAVE_GENERIC_VDSO. It will only have an effect when HAVE_GENERIC_VDSO is enabled anyways, but this makes the architecture Kconfig files a bit simpler. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://patch.msgid.link/20260709-vdso-have_generic_vdso-v1-2-d2e1061f268b@linutronix.de
2026-07-14syscall_user_dispatch: Introduce ARCH_SUPPORTS_SYSCALL_USER_DISPATCHJinjie Ruan
Currently, only x86 genuinely implements and supports Syscall User Dispatch (SUD). Multiple architectures provide a stub arch_syscall_is_vdso_sigreturn() returning 'false' simply to satisfy GENERIC_ENTRY compilation, which creates a false impression of feature support. Introduce ARCH_SUPPORTS_SYSCALL_USER_DISPATCH to decouple this mechanism from GENERIC_ENTRY. Select it exclusively on x86 and remove the redundant stub functions from other architectures. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://patch.msgid.link/20260713035422.582771-1-ruanjinjie@huawei.com
2026-07-12seccomp, treewide: Rename and convert __secure_computing() to return booleanJinjie Ruan
The return value of __secure_computing() currently uses 0 to indicate that a system call should be allowed, and -1 to indicate that it should be blocked/killed. This 0/-1 pattern is non-intuitive for a security check function and makes the control flow at the call sites less readable. Furthermore, any potential future changes to these return values would require a high-risk, error-prone audit of all its users across different architectures. Sanitize this logic by converting the return type of __secure_computing() to a proper boolean, where 'true' explicitly means 'allow' and 'false' means 'fail/deny'. Update all the two dozen or so call sites across the tree to align with this new boolean semantic. No functional changes are intended, as the callers still return -1 to the lower-level assembly entry code upon seccomp denial. Rename the function to __seccomp_permit_syscall() so that the purpose is entirely clear. [ tglx: Rename the function ] Suggested-by: Thomas Gleixner <tglx@kernel.org> Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com> Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Link: https://patch.msgid.link/20260707190254.230735780@kernel.org
2026-07-08syscall_user_dispatch: Make it configurable in KconfigGregory Price
Syscall User Dispatch is presently built under CONFIG_GENERIC_SYSCALL and cannot be disabled independently. Add CONFIG_SYSCALL_USER_DISPATCH to make it an optional feature. Signed-off-by: Gregory Price <gourry@gourry.net> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260706140020.873735-2-gourry@gourry.net
2026-06-15Merge tag 'locking-core-2026-06-14' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip 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 ...
2026-06-05kconfig: Remove the architecture specific config for PropellerRong Xu
The CONFIG_PROPELLER_CLANG option currently depends on ARCH_SUPPORTS_PROPELLER_CLANG, but this dependency seems unnecessary. Remove ARCH_SUPPORTS_PROPELLER_CLANG and allow users to control Propeller builds solely through CONFIG_PROPELLER_CLANG. This simplifies the kconfig and avoids potential confusion. Move the .llvm_bb_addr_map sections grouping to include/asm-generic/vmlinux.lds.h. The Propeller documentation has been updated to reflect the most recent tool location and now includes instructions for arm64. Contributor Acknowledgments: * SPE instructions: Daniel Hoekwater <hoekwater@google.com> Signed-off-by: Rong Xu <xur@google.com> Suggested-by: Will Deacon <will@kernel.org> Suggested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Yabin Cui <yabinc@google.com> Reviewed-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20260604195612.3757860-3-xur@google.com Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-06-05kconfig: Remove the architecture specific config for AutoFDORong Xu
The CONFIG_AUTOFDO_CLANG option currently depends on ARCH_SUPPORTS_AUTOFDO_CLANG, but this dependency seems unnecessary. Remove ARCH_SUPPORTS_AUTOFDO_CLANG and allow users to control AutoFDO builds solely through CONFIG_AUTOFDO_CLANG. This simplifies the kconfig and avoids potential confusion. Expand the AutoFDO documentation to include instructions for arm64. Contributor acknowledgments: * SPE instructions: Daniel Hoekwater <hoekwater@google.com> * ETM instructions: Yabin Cui <yabinc@google.com> Signed-off-by: Rong Xu <xur@google.com> Suggested-by: Will Deacon <will@kernel.org> Tested-by: Yabin Cui <yabinc@google.com> Reviewed-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20260604195612.3757860-2-xur@google.com Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-06-03uaccess: Provide unsafe_atomic_store_release_user()Thomas Gleixner
The upcoming support for unlocking robust futexes in the kernel requires store release semantics. Syscalls do not imply memory ordering on all architectures so the unlock operation requires a barrier. This barrier can be avoided when stores imply release like on x86. Provide a generic version with a smp_mb() before the unsafe_put_user(), which can be overridden by architectures. Provide also a ARCH_MEMORY_ORDER_TSO Kconfig option, which can be selected by architectures with Total Store Order (TSO), where store implies release, so that the smp_mb() in the generic implementation can be avoided. If that is set a barrier() is used instead of smp_mb(), which is not required for the use case at hand, but makes it future proof for other usage to prevent the compiler from reordering. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: André Almeida <andrealmeid@igalia.com> Link: https://patch.msgid.link/20260602090535.513181528@kernel.org
2026-05-29kbuild: distributed build support for Clang ThinLTORong Xu
Add distributed ThinLTO build support for the Linux kernel. This new mode offers several advantages: (1) Increased flexibility in handling user-specified build options. (2) Improved user-friendliness for developers. (3) Greater convenience for integrating with objtool and livepatch. Note that "distributed" in this context refers to a term that differentiates in-process ThinLTO builds by invoking backend compilation through the linker, not necessarily building in distributed environments. Distributed ThinLTO is enabled via the `CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example: > make LLVM=1 defconfig > scripts/config -e LTO_CLANG_THIN_DIST > make LLVM=1 oldconfig > make LLVM=1 vmlinux -j <..> The build flow proceeds in four stages: 1. Perform FE compilation, mirroring the in-process ThinLTO mode. 2. Thin-link the generated IR files and object files. 3. Find all IR files and perform BE compilation, using the flags stored in the .*.o.cmd files. 4. Link the BE results to generate the final vmlinux.o. NOTE: This patch currently implements the build for the main kernel image (vmlinux) only. Kernel module support is planned for a subsequent patch. Tested on the following arch: x86, arm64, loongarch, and riscv. The earlier implementation details can be found here: https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934 Signed-off-by: Rong Xu <xur@google.com> Co-developed-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Piotr Gorski <piotrgorski@cachyos.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Link: https://patch.msgid.link/20260529185347.2418373-4-xur@google.com Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-05-27arch/Kconfig: Remove tautological condition from AUTOFDO_CLANGNathan Chancellor
Now that the minimum supported version of LLVM for building the kernel has been raised to 17.0.1, the clang version check in CONFIG_AUTOFDO_CLANG can be removed because it is always true. Reviewed-by: Rong Xu <xur@google.com> Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-6-b3b8cda46bdd@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-05-27arch/Kconfig: Remove tautological conditions from HAS_LTO_CLANGNathan Chancellor
Now that the minimum supported version of LLVM for building the kernel has been raised to 17.0.1, two dependency lines in CONFIG_HAS_LTO_CLANG are always true because Clang will always be newer than 17.0.0, so they can be removed. Reviewed-by: Nicolas Schier <nsc@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-5-b3b8cda46bdd@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2026-04-18Merge tag 'parisc-for-7.1-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc architecture updates from Helge Deller: - A fix to make modules on 32-bit parisc architecture work again - Drop ip_fast_csum() inline assembly to avoid unaligned memory accesses - Allow to build kernel without 32-bit VDSO - Reference leak fix in error path in LED driver * tag 'parisc-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: led: fix reference leak on failed device registration module.lds.S: Fix modules on 32-bit parisc architecture parisc: Allow to build without VDSO32 parisc: Include 32-bit VDSO only when building for 32-bit or compat mode parisc: Allow to disable COMPAT mode on 64-bit kernel parisc: Fix default stack size when COMPAT=n parisc: Fix signal code to depend on CONFIG_COMPAT instead of CONFIG_64BIT parisc: is_compat_task() shall return false for COMPAT=n parisc: Avoid compat syscalls when COMPAT=n parisc: _llseek syscall is only available for 32-bit userspace parisc: Drop ip_fast_csum() inline assembly implementation parisc: update outdated comments for renamed ccio_alloc_consistent()
2026-04-17Merge tag 'integrity-v7.1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull integrity updates from Mimi Zohar: "There are two main changes, one feature removal, some code cleanup, and a number of bug fixes. Main changes: - Detecting secure boot mode was limited to IMA. Make detecting secure boot mode accessible to EVM and other LSMs - IMA sigv3 support was limited to fsverity. Add IMA sigv3 support for IMA regular file hashes and EVM portable signatures Remove: - Remove IMA support for asychronous hash calculation originally added for hardware acceleration Cleanup: - Remove unnecessary Kconfig CONFIG_MODULE_SIG and CONFIG_KEXEC_SIG tests - Add descriptions of the IMA atomic flags Bug fixes: - Like IMA, properly limit EVM "fix" mode - Define and call evm_fix_hmac() to update security.evm - Fallback to using i_version to detect file change for filesystems that do not support STATX_CHANGE_COOKIE - Address missing kernel support for configured (new) TPM hash algorithms - Add missing crypto_shash_final() return value" * tag 'integrity-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: evm: Enforce signatures version 3 with new EVM policy 'bit 3' integrity: Allow sigv3 verification on EVM_XATTR_PORTABLE_DIGSIG ima: add support to require IMA sigv3 signatures ima: add regular file data hash signature version 3 support ima: Define asymmetric_verify_v3() to verify IMA sigv3 signatures ima: remove buggy support for asynchronous hashes integrity: Eliminate weak definition of arch_get_secureboot() ima: Add code comments to explain IMA iint cache atomic_flags ima_fs: Correctly create securityfs files for unsupported hash algos ima: check return value of crypto_shash_final() in boot aggregate ima: Define and use a digest_size field in the ima_algo_desc structure powerpc/ima: Drop unnecessary check for CONFIG_MODULE_SIG ima: efi: Drop unnecessary check for CONFIG_MODULE_SIG/CONFIG_KEXEC_SIG ima: fallback to using i_version to detect file change evm: fix security.evm for a file with IMA signature s390: Drop unnecessary CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT evm: Don't enable fix mode when secure boot is enabled integrity: Make arch_ima_get_secureboot integrity-wide
2026-04-17module.lds.S: Fix modules on 32-bit parisc architectureHelge Deller
On the 32-bit parisc architecture, we always used the -ffunction-sections compiler option to tell the compiler to put the functions into seperate text sections. This is necessary, otherwise "big" kernel modules like ext4 or ipv6 fail to load because some branches won't be able to reach their stubs. Commit 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros") broke this for parisc because all text sections will get unconditionally merged now. Introduce the ARCH_WANTS_MODULES_TEXT_SECTIONS config option which avoids the text section merge for modules, and fix this issue by enabling this option by default for 32-bit parisc. Fixes: 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros") Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: stable@vger.kernel.org # v6.19+ Suggested-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-13Merge tag 'hardening-v7.1-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: - randomize_kstack: Improve implementation across arches (Ryan Roberts) - lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test - refcount: Remove unused __signed_wrap function annotations * tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test refcount: Remove unused __signed_wrap function annotations randomize_kstack: Unify random source across arches randomize_kstack: Maintain kstack_offset per task
2026-04-07rust: simplify `RUSTC_VERSION` Kconfig conditionsMiguel Ojeda
With the Rust version bump in place, several Kconfig conditions based on `RUSTC_VERSION` are always true. Thus simplify them. The minimum supported major LLVM version by our new Rust minimum version is now LLVM 18, instead of LLVM 16. However, there are no possible cleanups for `RUSTC_LLVM_VERSION`. Reviewed-by: Tamir Duberstein <tamird@kernel.org> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260405235309.418950-9-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-03-24randomize_kstack: Unify random source across archesRyan Roberts
Previously different architectures were using random sources of differing strength and cost to decide the random kstack offset. A number of architectures (loongarch, powerpc, s390, x86) were using their timestamp counter, at whatever the frequency happened to be. Other arches (arm64, riscv) were using entropy from the crng via get_random_u16(). There have been concerns that in some cases the timestamp counters may be too weak, because they can be easily guessed or influenced by user space. And get_random_u16() has been shown to be too costly for the level of protection kstack offset randomization provides. So let's use a common, architecture-agnostic source of entropy; a per-cpu prng, seeded at boot-time from the crng. This has a few benefits: - We can remove choose_random_kstack_offset(); That was only there to try to make the timestamp counter value a bit harder to influence from user space [*]. - The architecture code is simplified. All it has to do now is call add_random_kstack_offset() in the syscall path. - The strength of the randomness can be reasoned about independently of the architecture. - Arches previously using get_random_u16() now have much faster syscall paths, see below results. [*] Additionally, this gets rid of some redundant work on s390 and x86. Before this patch, those architectures called choose_random_kstack_offset() under arch_exit_to_user_mode_prepare(), which is also called for exception returns to userspace which were *not* syscalls (e.g. regular interrupts). Getting rid of choose_random_kstack_offset() avoids a small amount of redundant work for the non-syscall cases. In some configurations, add_random_kstack_offset() will now call instrumentable code, so for a couple of arches, I have moved the call a bit later to the first point where instrumentation is allowed. This doesn't impact the efficacy of the mechanism. There have been some claims that a prng may be less strong than the timestamp counter if not regularly reseeded. But the prng has a period of about 2^113. So as long as the prng state remains secret, it should not be possible to guess. If the prng state can be accessed, we have bigger problems. Additionally, we are only consuming 6 bits to randomize the stack, so there are only 64 possible random offsets. I assert that it would be trivial for an attacker to brute force by repeating their attack and waiting for the random stack offset to be the desired one. The prng approach seems entirely proportional to this level of protection. Performance data are provided below. The baseline is v6.18 with rndstack on for each respective arch. (I)/(R) indicate statistically significant improvement/regression. arm64 platform is AWS Graviton3 (m7g.metal). x86_64 platform is AWS Sapphire Rapids (m7i.24xlarge): +-----------------+--------------+---------------+---------------+ | Benchmark | Result Class | per-cpu-prng | per-cpu-prng | | | | arm64 (metal) | x86_64 (VM) | +=================+==============+===============+===============+ | syscall/getpid | mean (ns) | (I) -9.50% | (I) -17.65% | | | p99 (ns) | (I) -59.24% | (I) -24.41% | | | p99.9 (ns) | (I) -59.52% | (I) -28.52% | +-----------------+--------------+---------------+---------------+ | syscall/getppid | mean (ns) | (I) -9.52% | (I) -19.24% | | | p99 (ns) | (I) -59.25% | (I) -25.03% | | | p99.9 (ns) | (I) -59.50% | (I) -28.17% | +-----------------+--------------+---------------+---------------+ | syscall/invalid | mean (ns) | (I) -10.31% | (I) -18.56% | | | p99 (ns) | (I) -60.79% | (I) -20.06% | | | p99.9 (ns) | (I) -61.04% | (I) -25.04% | +-----------------+--------------+---------------+---------------+ I tested an earlier version of this change on x86 bare metal and it showed a smaller but still significant improvement. The bare metal system wasn't available this time around so testing was done in a VM instance. I'm guessing the cost of rdtsc is higher for VMs. Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://patch.msgid.link/20260303150840.3789438-3-ryan.roberts@arm.com Signed-off-by: Kees Cook <kees@kernel.org>
2026-03-13integrity: Eliminate weak definition of arch_get_secureboot()Nathan Chancellor
security/integrity/secure_boot.c contains a single __weak function, which breaks recordmcount when building with clang: $ make -skj"$(nproc)" ARCH=powerpc LLVM=1 ppc64_defconfig security/integrity/secure_boot.o Cannot find symbol for section 2: .text. security/integrity/secure_boot.o: failed Introduce a Kconfig symbol, CONFIG_HAVE_ARCH_GET_SECUREBOOT, to indicate that an architecture provides a definition of arch_get_secureboot(). Provide a static inline stub when this symbol is not defined to achieve the same effect as the __weak function, allowing secure_boot.c to be removed altogether. Move the s390 definition of arch_get_secureboot() out of the CONFIG_KEXEC_FILE block to ensure it is always available, as it does not actually depend on KEXEC_FILE. Reported-by: Arnd Bergmann <arnd@arndb.de> Fixes: 31a6a07eefeb ("integrity: Make arch_ima_get_secureboot integrity-wide") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2026-01-12sched: Move clock related paravirt code to kernel/schedJuergen Gross
Paravirt clock related functions are available in multiple archs. In order to share the common parts, move the common static keys to kernel/sched/ and remove them from the arch specific files. Make a common paravirt_steal_clock() implementation available in kernel/sched/cputime.c, guarding it with a new config option CONFIG_HAVE_PV_STEAL_CLOCK_GEN, which can be selected by an arch in case it wants to use that common variant. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260105110520.21356-7-jgross@suse.com
2025-11-12treewide: drop outdated compiler version remarks in Kconfig help textsLukas Bulwahn
As of writing, Documentation/Changes states the minimal versions of GNU C being 8.1, Clang being 15.0.0 and binutils being 2.30. A few Kconfig help texts are pointing out that specific GCC and Clang versions are needed, but by now, those pointers to versions, such later than 4.0, later than 4.4, or clang later than 5.0, are obsolete and unlikely to be found by users configuring their kernel builds anyway. Drop these outdated remarks in Kconfig help texts referring to older compiler and binutils versions. No functional change. Link: https://lkml.kernel.org/r/20251010082138.185752-1-lukas.bulwahn@redhat.com Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Russel King <linux@armlinux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-10-29compiler_types: Introduce __nocfi_genericNathan Chancellor
There are two different ways that LLVM can expand kCFI operand bundles in LLVM IR: generically in the middle end or using an architecture specific sequence when lowering LLVM IR to machine code in the backend. The generic pass allows any architecture to take advantage of kCFI but the expansion of these bundles in the middle end can mess with optimizations that may turn indirect calls into direct calls when the call target is known at compile time, such as after inlining. Add __nocfi_generic, dependent on an architecture selecting CONFIG_ARCH_USES_CFI_GENERIC_LLVM_PASS, to disable kCFI bundle generation in functions where only the generic kCFI pass may cause problems. Link: https://github.com/ClangBuiltLinux/linux/issues/2124 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Link: https://patch.msgid.link/20251025-idpf-fix-arm-kcfi-build-error-v1-1-ec57221153ae@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2025-10-09rust: cfi: only 64-bit arm and x86 support CFI_CLANGConor Dooley
The kernel uses the standard rustc targets for non-x86 targets, and out of those only 64-bit arm's target has kcfi support enabled. For x86, the custom 64-bit target enables kcfi. The HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC config option that allows CFI_CLANG to be used in combination with RUST does not check whether the rustc target supports kcfi. This breaks the build on riscv (and presumably 32-bit arm) when CFI_CLANG and RUST are enabled at the same time. Ordinarily, a rustc-option check would be used to detect target support but unfortunately rustc-option filters out the target for reasons given in commit 46e24a545cdb4 ("rust: kasan/kbuild: fix missing flags on first build"). As a result, if the host supports kcfi but the target does not, e.g. when building for riscv on x86_64, the build would remain broken. Instead, make HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC depend on the only two architectures where the target used supports it to fix the build. CC: stable@vger.kernel.org Fixes: ca627e636551e ("rust: cfi: add support for CFI_CLANG with Rust") Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250908-distill-lint-1ae78bcf777c@spud Signed-off-by: Paul Walmsley <pjw@kernel.org>
2025-10-01Merge tag 'kbuild-6.18-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux Pull Kbuild updates from Nathan Chancellor: - Extend modules.builtin.modinfo to include module aliases from MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such as kmod) can verify that a particular module alias will be handled by a builtin module - Bump the minimum version of LLVM for building the kernel to 15.0.0 - Upgrade several userspace API checks in headers_check.pl to errors - Unify and consolidate CONFIG_WERROR / W=e handling - Turn assembler and linker warnings into errors with CONFIG_WERROR / W=e - Respect CONFIG_WERROR / W=e when building userspace programs (userprogs) - Enable -Werror unconditionally when building host programs (hostprogs) - Support copy_file_range() and data segment alignment in gen_init_cpio to improve performance on filesystems that support reflinks such as btrfs and XFS - Miscellaneous small changes to scripts and configuration files * tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits) modpost: Initialize builtin_modname to stop SIGSEGVs Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o modpost: Create modalias for builtin modules modpost: Add modname to mod_device_table alias scsi: Always define blogic_pci_tbl structure kbuild: extract modules.builtin.modinfo from vmlinux.unstripped kbuild: keep .modinfo section in vmlinux.unstripped kbuild: always create intermediate vmlinux.unstripped s390: vmlinux.lds.S: Reorder sections KMSAN: Remove tautological checks objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs riscv: Unconditionally use linker relaxation riscv: Remove version check for LTO_CLANG selects powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault() mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER arm64: Remove tautological LLVM Kconfig conditions ARM: Clean up definition of ARM_HAS_GROUP_RELOCS ...
2025-09-30Merge tag 'timers-vdso-2025-09-29' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull VDSO updates from Thomas Gleixner: - Further consolidation of the VDSO infrastructure and the common data store - Simplification of the related Kconfig logic - Improve the VDSO selftest suite * tag 'timers-vdso-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: selftests: vDSO: Drop vdso_test_clock_getres selftests: vDSO: vdso_test_abi: Add tests for clock_gettime64() selftests: vDSO: vdso_test_abi: Test CPUTIME clocks selftests: vDSO: vdso_test_abi: Use explicit indices for name array selftests: vDSO: vdso_test_abi: Drop clock availability tests selftests: vDSO: vdso_test_abi: Use ksft_finished() selftests: vDSO: vdso_test_abi: Correctly skip whole test with missing vDSO selftests: vDSO: Fix -Wunitialized in powerpc VDSO_CALL() wrapper vdso: Add struct __kernel_old_timeval forward declaration to gettime.h vdso: Gate VDSO_GETRANDOM behind HAVE_GENERIC_VDSO vdso: Drop Kconfig GENERIC_VDSO_TIME_NS vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE vdso: Drop kconfig GENERIC_COMPAT_VDSO vdso: Drop kconfig GENERIC_VDSO_32 riscv: vdso: Untangle Kconfig logic time: Build generic update_vsyscall() only with generic time vDSO vdso/gettimeofday: Remove !CONFIG_TIME_NS stubs vdso: Move ENABLE_COMPAT_VDSO from core to arm64 ARM: VDSO: Remove cntvct_ok global variable vdso/datastore: Gate time data behind CONFIG_GENERIC_GETTIMEOFDAY
2025-09-30Merge tag 'core-core-2025-09-29' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull TIF bit unification updates from Thomas Gleixner: "A set of changes to consolidate the generic TIF (thread info flag) bits accross architectures. All architectures define the same set of generic TIF bits. This makes it pointlessly hard to add a new generic TIF bit or to change an existing one. Provide a generic variant and convert the architectures which utilize the generic entry code over to use it. The TIF space is divided into 16 generic bits and 16 architecture specific bits, which turned out to provide enough space on both sides" * tag 'core-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: LoongArch: Fix bitflag conflict for TIF_FIXADE riscv: Use generic TIF bits loongarch: Use generic TIF bits s390/entry: Remove unused TIF flags s390: Use generic TIF bits x86: Use generic TIF bits asm-generic: Provide generic TIF infrastructure
2025-09-30Merge tag 'sched-core-2025-09-26' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "Core scheduler changes: - Make migrate_{en,dis}able() inline, to improve performance (Menglong Dong) - Move STDL_INIT() functions out-of-line (Peter Zijlstra) - Unify the SCHED_{SMT,CLUSTER,MC} Kconfig (Peter Zijlstra) Fair scheduling: - Defer throttling to when tasks exit to user-space, to reduce the chance & impact of throttle-preemption with held locks and other resources (Aaron Lu, Valentin Schneider) - Get rid of sched_domains_curr_level hack for tl->cpumask(), as the warning was getting triggered on certain topologies (Peter Zijlstra) Misc cleanups & fixes: - Header cleanups (Menglong Dong) - Fix race in push_dl_task() (Harshit Agarwal)" * tag 'sched-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix some typos in include/linux/preempt.h sched: Make migrate_{en,dis}able() inline rcu: Replace preempt.h with sched.h in include/linux/rcupdate.h arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c sched/fair: Do not balance task to a throttled cfs_rq sched/fair: Do not special case tasks in throttled hierarchy sched/fair: update_cfs_group() for throttled cfs_rqs sched/fair: Propagate load for throttled cfs_rq sched/fair: Get rid of throttled_lb_pair() sched/fair: Task based throttle time accounting sched/fair: Switch to task based throttle model sched/fair: Implement throttle task work and related helpers sched/fair: Add related data structure for task based throttle sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig sched: Move STDL_INIT() functions out-of-line sched/fair: Get rid of sched_domains_curr_level hack for tl->cpumask() sched/deadline: Fix race in push_dl_task()
2025-09-24kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFIKees Cook
The kernel's CFI implementation uses the KCFI ABI specifically, and is not strictly tied to a particular compiler. In preparation for GCC supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with associated options). Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will enable CONFIG_CFI during olddefconfig. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2025-09-17asm-generic: Provide generic TIF infrastructureThomas Gleixner
Common TIF bits do not have to be defined by every architecture. They can be defined in a generic header. That allows adding generic TIF bits without chasing a gazillion of architecture headers, which is again a unjustified burden on anyone who works on generic infrastructure as it always needs a boat load of work to keep existing architecture code working when adding new stuff. While it is not as horrible as the ignorance of the generic entry infrastructure, it is a welcome mechanism to make architecture people rethink their approach of just leaching generic improvements into architecture code and thereby making it accumulatingly harder to maintain and improve generic code. It's about time that this changes. Provide the infrastructure and split the TIF space in half, 16 generic and 16 architecture specific bits. This could probably be extended by TIF_SINGLESTEP and BLOCKSTEP, but those are only used in architecture specific code. So leave them alone for now. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2025-09-04vdso: Drop Kconfig GENERIC_VDSO_DATA_STOREThomas Weißschuh
All users of the generic vDSO library also use the generic vDSO datastore. Remove the now unnecessary Kconfig symbol. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/all/20250826-vdso-cleanups-v1-9-d9b65750e49f@linutronix.de
2025-09-03sched: Unify the SCHED_{SMT,CLUSTER,MC} KconfigPeter Zijlstra
Like many Kconfig symbols, SCHED_{SMT,CLUSTER,MC} are duplicated across arch/*/Kconfig. Try and clean up a little. Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com> Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com> # powerpc Link: https://lkml.kernel.org/r/20250826094358.GG3245006@noisy.programming.kicks-ass.net
2025-08-28arch/Kconfig: Drop always true condition from RANDOMIZE_KSTACK_OFFSETNathan Chancellor
Now that the minimum supported version of LLVM for building the kernel has been bumped to 15.0.0, the second depends line in RANDOMIZE_KSTACK_OFFSET is always true, so it can be removed. Reviewed-by: Kees Cook <kees@kernel.org> Link: https://lore.kernel.org/r/20250821-bump-min-llvm-ver-15-v2-2-635f3294e5f0@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2025-08-01Merge tag 'trace-deferred-unwind-v6.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull initial deferred unwind infrastructure from Steven Rostedt: "This is the core infrastructure for the deferred unwinder that is required for sframes[1]. Several other patch series are based on this work although those patch series are not dependent on each other. In order to simplify the development, having this core series upstream will allow the other series to be worked on in parallel. The other series are: - The two patches to implement x86 support [2] [3] - The s390 work [4] - The perf work [5] - The ftrace work [6] - The sframe work [7] And more is on the way. The core infrastructure adds the following in kernel APIs: - int unwind_user_faultable(struct unwind_stacktrace *trace); Performs a user space stack trace that may fault user pages in. - int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func); Allows a tracer to register with the unwind deferred infrastructure. - int unwind_deferred_request(struct unwind_work *work, u64 *cookie); Used when a tracer request a deferred trace. Can be called from interrupt or NMI context. - void unwind_deferred_cancel(struct unwind_work *work); Called by a tracer to unregister from the deferred unwind infrastructure. - void unwind_deferred_task_exit(struct task_struct *task); Called by task exit code to flush any pending unwind requests. - void unwind_task_init(struct task_struct *task); Called by do_fork() to initialize the task struct for the deferred unwinder. - void unwind_task_free(struct task_struct *task); Called by do_exit() to free up any resources used by the deferred unwinder. None of the above is actually compiled unless an architecture enables it, which none currently do" Link: https://sourceware.org/binutils/wiki/sframe [1] Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.260781923@kernel.org/ [2] Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.432327787@kernel.org/ [3] Link: https://lore.kernel.org/linux-trace-kernel/20250710163522.3195293-1-jremus@linux.ibm.com/ [4] Link: https://lore.kernel.org/linux-trace-kernel/20250718164119.089692174@kernel.org/ [5] Link: https://lore.kernel.org/linux-trace-kernel/20250424192612.505622711@goodmis.org/ [6] Link: https://lore.kernel.org/linux-trace-kernel/20250717012848.927473176@kernel.org/ [7] * tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: unwind: Finish up unwind when a task exits unwind deferred: Use SRCU unwind_deferred_task_work() unwind: Add USED bit to only have one conditional on way back to user space unwind deferred: Add unwind_completed mask to stop spurious callbacks unwind deferred: Use bitmask to determine which callbacks to call unwind_user/deferred: Make unwind deferral requests NMI-safe unwind_user/deferred: Add deferred unwinding interface unwind_user/deferred: Add unwind cache unwind_user/deferred: Add unwind_user_faultable() unwind_user: Add user space unwinding API with frame pointer support
2025-07-29Merge tag 'x86_bugs_for_v6.17_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 CPU mitigation updates from Borislav Petkov: - Untangle the Retbleed from the ITS mitigation on Intel. Allow for ITS to enable stuffing independently from Retbleed, do some cleanups to simplify and streamline the code - Simplify SRSO and make mitigation types selection more versatile depending on the Retbleed mitigation selection. Simplify code some - Add the second part of the attack vector controls which provide a lot friendlier user interface to the speculation mitigations than selecting each one by one as it is now. Instead, the selection of whole attack vectors which are relevant to the system in use can be done and protection against only those vectors is enabled, thus giving back some performance to the users * tag 'x86_bugs_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/bugs: Print enabled attack vectors x86/bugs: Add attack vector controls for TSA x86/pti: Add attack vector controls for PTI x86/bugs: Add attack vector controls for ITS x86/bugs: Add attack vector controls for SRSO x86/bugs: Add attack vector controls for L1TF x86/bugs: Add attack vector controls for spectre_v2 x86/bugs: Add attack vector controls for BHI x86/bugs: Add attack vector controls for spectre_v2_user x86/bugs: Add attack vector controls for retbleed x86/bugs: Add attack vector controls for spectre_v1 x86/bugs: Add attack vector controls for GDS x86/bugs: Add attack vector controls for SRBDS x86/bugs: Add attack vector controls for RFDS x86/bugs: Add attack vector controls for MMIO x86/bugs: Add attack vector controls for TAA x86/bugs: Add attack vector controls for MDS x86/bugs: Define attack vectors relevant for each bug x86/Kconfig: Add arch attack vector support cpu: Define attack vectors ...
2025-07-29Merge tag 'core-entry-2025-07-29' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull generic entry code updates from Thomas Gleixner: - Split the code into syscall and exception/interrupt parts to ease the conversion of ARM[64] to the generic entry infrastructure - Extend syscall user dispatching to support a single intercepted range instead of the default single non-intercepted range. That allows monitoring/analysis of a specific executable range, e.g. a library, and also provides flexibility for sandboxing scenarios - Cleanup and extend the user dispatch selftest * tag 'core-entry-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: entry: Split generic entry into generic exception and syscall entry selftests: Add tests for PR_SYS_DISPATCH_INCLUSIVE_ON syscall_user_dispatch: Add PR_SYS_DISPATCH_INCLUSIVE_ON selftests: Fix errno checking in syscall_user_dispatch test
2025-07-29unwind_user: Add user space unwinding API with frame pointer supportJosh Poimboeuf
Introduce a generic API for unwinding user stacks. In order to expand user space unwinding to be able to handle more complex scenarios, such as deferred unwinding and reading user space information, create a generic interface that all architectures can use that support the various unwinding methods. This is an alternative method for handling user space stack traces from the simple stack_trace_save_user() API. This does not replace that interface, but this interface will be used to expand the functionality of user space stack walking. None of the structures introduced will be exposed to user space tooling. Support for frame pointer unwinding is added. For an architecture to support frame pointer unwinding it needs to enable CONFIG_HAVE_UNWIND_USER_FP and define ARCH_INIT_USER_FP_FRAME. By encoding the frame offsets in struct unwind_user_frame, much of this code can also be reused for future unwinder implementations like sframe. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Indu Bhagat <indu.bhagat@oracle.com> Cc: "Jose E. Marchesi" <jemarch@gnu.org> Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Florian Weimer <fweimer@redhat.com> Cc: Sam James <sam@gentoo.org> Link: https://lore.kernel.org/20250729182404.975790139@kernel.org Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Co-developed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/all/20250710164301.3094-2-mathieu.desnoyers@efficios.com/ Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Co-developed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-21stackleak: Rename STACKLEAK to KSTACK_ERASEKees Cook
In preparation for adding Clang sanitizer coverage stack depth tracking that can support stack depth callbacks: - Add the new top-level CONFIG_KSTACK_ERASE option which will be implemented either with the stackleak GCC plugin, or with the Clang stack depth callback support. - Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE, but keep it for anything specific to the GCC plugin itself. - Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named for what it does rather than what it protects against), but leave as many of the internals alone as possible to avoid even more churn. While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS, since that's the only place it is referenced from. Suggested-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2025-07-11x86/Kconfig: Add arch attack vector supportDavid Kaplan
ARCH_HAS_CPU_ATTACK_VECTORS should be set for architectures which implement the new attack-vector based controls for CPU mitigations. If an arch does not support attack-vector based controls then an attempt to use them results in a warning. Signed-off-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250707183316.1349127-4-david.kaplan@amd.com
2025-06-30entry: Split generic entry into generic exception and syscall entryJinjie Ruan
Currently CONFIG_GENERIC_ENTRY enables both the generic exception entry logic and the generic syscall entry logic, which are otherwise loosely coupled. Introduce separate config options for these so that architectures can select the two independently. This will make it easier for architectures to migrate to generic entry code. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/20250213130007.1418890-2-ruanjinjie@huawei.com Link: https://lore.kernel.org/all/20250624-generic-entry-split-v1-1-53d5ef4f94df@linaro.org [Linus Walleij: rebase onto v6.16-rc1]
2025-05-16fs/resctrl: Add boiler plate for external resctrl codeJames Morse
Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL for the common parts of the resctrl interface and make X86_CPU_RESCTRL select this. Adding an include of asm/resctrl.h to linux/resctrl.h allows the /fs/resctrl files to switch over to using this header instead. Co-developed-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-16-james.morse@arm.com
2025-04-05Merge tag 'kbuild-v6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Improve performance in gendwarfksyms - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS - Support CONFIG_HEADERS_INSTALL for ARCH=um - Use more relative paths to sources files for better reproducibility - Support the loong64 Debian architecture - Add Kbuild bash completion - Introduce intermediate vmlinux.unstripped for architectures that need static relocations to be stripped from the final vmlinux - Fix versioning in Debian packages for -rc releases - Treat missing MODULE_DESCRIPTION() as an error - Convert Nios2 Makefiles to use the generic rule for built-in DTB - Add debuginfo support to the RPM package * tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits) kbuild: rpm-pkg: build a debuginfo RPM kconfig: merge_config: use an empty file as initfile nios2: migrate to the generic rule for built-in DTB rust: kbuild: skip `--remap-path-prefix` for `rustdoc` kbuild: pacman-pkg: hardcode module installation path kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally modpost: require a MODULE_DESCRIPTION() kbuild: make all file references relative to source root x86: drop unnecessary prefix map configuration kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS kbuild: Add a help message for "headers" kbuild: deb-pkg: remove "version" variable in mkdebian kbuild: deb-pkg: fix versioning for -rc releases Documentation/kbuild: Fix indentation in modules.rst example x86: Get rid of Makefile.postlink kbuild: Create intermediate vmlinux build with relocations preserved kbuild: Introduce Kconfig symbol for linking vmlinux with relocations kbuild: link-vmlinux.sh: Make output file name configurable kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y Revert "kheaders: Ignore silly-rename files" ...
2025-03-17kbuild: Introduce Kconfig symbol for linking vmlinux with relocationsArd Biesheuvel
Some architectures build vmlinux with static relocations preserved, but strip them again from the final vmlinux image. Arch specific tools consume these static relocations in order to construct relocation tables for KASLR. The fact that vmlinux is created, consumed and subsequently updated goes against the typical, declarative paradigm used by Make, which is based on rules and dependencies. So as a first step towards cleaning this up, introduce a Kconfig symbol to declare that the arch wants to consume the static relocations emitted into vmlinux. This will be wired up further in subsequent patches. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-02-21vdso: Add generic architecture-specific data storageThomas Weißschuh
Some architectures need to expose architecture-specific data to the vDSO. Enable the generic vDSO storage mechanism to both store and map this data. Some architectures require more than a single page, like LoongArch, so prepare for that usecase, too. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-7-13a4669dfc8c@linutronix.de