Commit Graph

582 Commits

Author SHA1 Message Date
Linus Torvalds
7d1f84f1b9 mm.git review status for linus..mm-nonmm-stable
Total patches:       134
 Fixes: tags:         86
 cc:stable patches:   52
 Reviews/patch:       0.73
 Reviewed rate:       59%
 
 Summary of patch series in this merge:
 
 - "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 (Google)):
 
   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.
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Merge tag 'mm-nonmm-stable-2026-10-25-14-57' of 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
  ...
2026-10-27 12:08:22 -10:00
Linus Torvalds
c5fd5e67c7 mm.git review status for linus..mm-stable
Everything:
 
 Total patches:       539
 Fixes: tags:         101
 cc:stable patches:   67
 Reviews/patch:       1.62
 Reviewed rate:       76%
 
 Excluding DAMON:
 
 Total patches:       407
 Fixes: tags:         84
 cc:stable patches:   44
 Reviews/patch:       2.00
 Reviewed rate:       87%
 
 Excluding DAMON and selftests:
 
 Total patches:       360
 Fixes: tags:         78
 cc:stable patches:   44
 Reviews/patch:       2.02
 Reviewed rate:       89%
 
 Summary of patch series in this merge, ordered by descending size:
 
 - "selftests/mm: improve khugepaged coverage" (Kiryl Shutsemau (Meta)):
 
   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 (ARM)):
 
   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
   (Microsoft)):
 
   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
   (Xiaomi)):
 
   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 (Huawei)):
 
   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 (Huawei)):
 
   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 (Huawei)):
 
   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 (Microsoft)):
 
   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.
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Merge tag 'mm-stable-2026-10-19-21-33' of 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
  ...
2026-10-23 07:42:11 -10:00
Lorenzo Stoakes (ARM)
35e340a478 mm: userland pgtable freeing is RCU-safe now, remove leftover bits
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 1fb3d8c20b ("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>
2026-10-08 22:54:52 -07:00
Julian Braha
8cdae75ceb arch/Kconfig: fix dead conditions by removing dead options
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>
2026-10-06 19:03:00 -07:00
Mark Rutland
5b9a28eeed sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY}
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
2026-09-02 09:37:23 +02:00
Linus Torvalds
104a813376 VDSO updates:
- 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
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Merge tag 'timers-vdso-2026-08-17' of 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
  ...
2026-08-18 16:56:25 -07:00
Linus Torvalds
030c9f813b Treewide timer related cleanups:
- 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.
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Merge tag 'timers-cleanups-2026-08-17' of 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
2026-08-18 15:58:29 -07:00
Thomas Gleixner
dfc256dac5 calibrate: Rework delay timer calibration
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
2026-07-15 15:04:55 +02:00
Thomas Weißschuh
a924263758 vdso: Remove the dependency on HAVE_GENERIC_VDSO from ARCH_HAS_VDSO_ARCH_DATA
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
2026-07-15 10:49:02 +02:00
Jinjie Ruan
8383e05af7 syscall_user_dispatch: Introduce ARCH_SUPPORTS_SYSCALL_USER_DISPATCH
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
2026-07-14 16:34:07 +02:00
Jinjie Ruan
7ba2ba7471 seccomp, treewide: Rename and convert __secure_computing() to return boolean
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
2026-07-12 12:38:02 +02:00
Gregory Price
ee935e8dc7 syscall_user_dispatch: Make it configurable in Kconfig
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
2026-07-08 10:22:00 +02:00
Linus Torvalds
764e77d868 Locking updates for v7.2:
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.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2026-06-14' of 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
  ...
2026-06-15 14:21:14 +05:30
Rong Xu
2566fa7b2f
kconfig: Remove the architecture specific config for Propeller
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>
2026-06-05 21:12:08 -07:00
Rong Xu
e88b2fe8b9
kconfig: Remove the architecture specific config for AutoFDO
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>
2026-06-05 21:12:08 -07:00
Thomas Gleixner
6149fc36c0 uaccess: Provide unsafe_atomic_store_release_user()
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
2026-06-03 11:38:50 +02:00
Rong Xu
9f2aee8f7d
kbuild: distributed build support for Clang ThinLTO
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>
2026-05-29 13:44:29 -07:00
Nathan Chancellor
de0bf1e138
arch/Kconfig: Remove tautological condition from AUTOFDO_CLANG
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>
2026-05-27 15:20:04 -07:00
Nathan Chancellor
2189cb1a80
arch/Kconfig: Remove tautological conditions from HAS_LTO_CLANG
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>
2026-05-27 15:20:04 -07:00
Linus Torvalds
eb5249b125 parisc architecture fixes and updates for kernel v7.1-rc1:
- 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
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Merge tag 'parisc-for-7.1-rc1' of 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()
2026-04-18 11:37:36 -07:00
Linus Torvalds
9cdca33667 integrity-v7.1
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Merge tag 'integrity-v7.1' of 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
2026-04-17 15:42:01 -07:00
Helge Deller
1221365f55 module.lds.S: Fix modules on 32-bit parisc architecture
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 1ba9f89794 ("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: 1ba9f89794 ("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>
2026-04-17 15:46:46 +02:00
Linus Torvalds
d568788baa hardening updates for v7.1-rc1
- randomize_kstack: Improve implementation across arches (Ryan Roberts)
 
 - lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test
 
 - refcount: Remove unused __signed_wrap function annotations
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Merge tag 'hardening-v7.1-rc1' of 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
2026-04-13 17:52:29 -07:00
Miguel Ojeda
b28711ac98 rust: simplify RUSTC_VERSION Kconfig conditions
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>
2026-04-07 10:00:23 +02:00
Ryan Roberts
a96ef5848c randomize_kstack: Unify random source across arches
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>
2026-03-24 21:12:03 -07:00
Nathan Chancellor
7caedbb5ad integrity: Eliminate weak definition of arch_get_secureboot()
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: 31a6a07eef ("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>
2026-03-13 11:37:13 -04:00
Juergen Gross
e6b2aa6d40 sched: Move clock related paravirt code to kernel/sched
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
2026-01-12 15:39:14 +01:00
Lukas Bulwahn
cd4eaccc00 treewide: drop outdated compiler version remarks in Kconfig help texts
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>
2025-11-12 10:00:14 -08:00
Nathan Chancellor
39c89ee6e9 compiler_types: Introduce __nocfi_generic
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>
2025-10-29 20:04:55 -07:00
Conor Dooley
812258ff41 rust: cfi: only 64-bit arm and x86 support CFI_CLANG
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 46e24a545c ("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: ca627e6365 ("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>
2025-10-09 19:36:45 -06:00
Linus Torvalds
7f70725741 Kbuild updates for 6.18
- 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.
 
 Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Merge tag 'kbuild-6.18-1' of 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
  ...
2025-10-01 20:58:51 -07:00
Linus Torvalds
4b81e2eb9e Updates for the VDSO subsystem:
- Further consolidation of the VDSO infrastructure and the common data
     store.
 
   - Simplification of the related Kconfig logic
 
   - Improve the VDSO selftest suite
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Merge tag 'timers-vdso-2025-09-29' of 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
2025-09-30 16:58:21 -07:00
Linus Torvalds
7601d18be0 A set of changes to consolidate the generic TIF 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.
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Merge tag 'core-core-2025-09-29' of 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
2025-09-30 14:36:20 -07:00
Linus Torvalds
6c7340a7a8 Scheduler updates for v6.18:
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 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)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2025-09-26' of 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()
2025-09-30 10:35:11 -07:00
Kees Cook
23ef9d4397 kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
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>
2025-09-24 14:29:14 -07:00
Thomas Gleixner
2958934348 asm-generic: Provide generic TIF infrastructure
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>
2025-09-17 08:14:03 +02:00
Thomas Weißschuh
7b338f6d4e vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE
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
2025-09-04 11:23:50 +02:00
Peter Zijlstra
7bd291abe2 sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig
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
2025-09-03 10:03:13 +02:00
Nathan Chancellor
65aebf6f58
arch/Kconfig: Drop always true condition from RANDOMIZE_KSTACK_OFFSET
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>
2025-08-28 16:58:43 -07:00
Linus Torvalds
c6439bfaab Deferred unwind changes for 6.17
This is the core infrastructure for the deferred unwinder that is required
 for sframes[1]. Several other patch series is 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:
   https://lore.kernel.org/linux-trace-kernel/20250717004958.260781923@kernel.org/
   https://lore.kernel.org/linux-trace-kernel/20250717004958.432327787@kernel.org/
 
 - The s390 work:
   https://lore.kernel.org/linux-trace-kernel/20250710163522.3195293-1-jremus@linux.ibm.com/
 
 - The perf work:
   https://lore.kernel.org/linux-trace-kernel/20250718164119.089692174@kernel.org/
 
 - The ftrace work:
   https://lore.kernel.org/linux-trace-kernel/20250424192612.505622711@goodmis.org/
 
 - The sframe work:
   https://lore.kernel.org/linux-trace-kernel/20250717012848.927473176@kernel.org/
 
 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.
 
 [1] https://sourceware.org/binutils/wiki/sframe
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Merge tag 'trace-deferred-unwind-v6.17' of 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
2025-08-01 09:46:24 -07:00
Linus Torvalds
04d29e3609 - 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
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Merge tag 'x86_bugs_for_v6.17_rc1' of 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
  ...
2025-07-29 16:34:45 -07:00
Linus Torvalds
78bb43e51b Updates for the generic entry code:
- 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
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Merge tag 'core-entry-2025-07-29' of 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
2025-07-29 15:14:29 -07:00
Josh Poimboeuf
71753c6ed2 unwind_user: Add user space unwinding API with frame pointer support
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>
2025-07-29 14:46:07 -04:00
Kees Cook
57fbad15c2 stackleak: Rename STACKLEAK to KSTACK_ERASE
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>
2025-07-21 21:35:01 -07:00
David Kaplan
735e59204b x86/Kconfig: Add arch attack vector support
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
2025-07-11 17:56:40 +02:00
Jinjie Ruan
a70e9f647f entry: Split generic entry into generic exception and syscall entry
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]
2025-06-30 19:52:55 +02:00
James Morse
bff70402d6 fs/resctrl: Add boiler plate for external resctrl code
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
2025-05-16 11:05:40 +02:00
Linus Torvalds
f4d2ef4825 Kbuild updates for v6.15
- 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
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Merge tag 'kbuild-v6.15' of 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"
  ...
2025-04-05 15:46:50 -07:00
Ard Biesheuvel
9b400d1725 kbuild: Introduce Kconfig symbol for linking vmlinux with relocations
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>
2025-03-17 00:29:50 +09:00
Thomas Weißschuh
365841e155 vdso: Add generic architecture-specific data storage
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
2025-02-21 09:54:01 +01:00