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Pull dma-mapping fixes from Marek Szyprowski:
"A few fixes for the DMA-mapping code:
- resolved regression in accessing encrypted memory by IOMMU-backed
devices (Aneesh Kumar K.V)
- improved failure handling and removed rare bug in swiotlb/highmem
(Donggeun Yoo)"
* tag 'dma-mapping-7.3-2026-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
x86/mm: Don't force unencrypted DMA for IOMMU-backed devices
dma-mapping: don't trace the DMA address when the allocation fails
swiotlb: use the adjusted address for the highmem page lookup
dma-coherent: report a failed reserved memory assignment
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Commit 8277a12d0d60 ("dma-pool: track decrypted atomic pools and select
them via attrs") exposed an issue with force_dma_unencrypted() on
systems using host memory encryption.
force_dma_unencrypted() checks whether the device DMA mask can address
the encryption bit and, if not, requires DMA allocations to use
unencrypted memory. However, this check is not applicable when the
device is using the IOMMU. In that case, the device DMA mask constrains
the IOVA seen by the device, not the backing physical address, so it
does not need to cover the C-bit.
This currently causes dma_alloc_attrs() to set
__DMA_ATTR_ALLOC_CC_SHARED for such devices. iommu_dma_alloc() does not
support that attribute and rejects the allocation, causing DMA
allocations to fail.
Do not force DMA allocations to be unencrypted when the device is using
the IOMMU. This allows the IOMMU to map the encrypted physical pages as
before and avoids incorrectly requesting CC_SHARED allocations.
Fixes: 8277a12d0d60 ("dma-pool: track decrypted atomic pools and select them via attrs")
Reported-by: Timo Witte <timo.witte@gmail.com>
Closes: https://lore.kernel.org/all/CANB4YXS=Nf-co3t8eMHtqrW4sn=1BDcP6o=EoTrgZm0WYMYTyw@mail.gmail.com/
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Link: https://lore.kernel.org/r/20260908113232.247457-1-aneesh.kumar@kernel.org
[mszyprow: adjusted url and changed 'link' tag to the 'closes' one]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
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A PTE is allocated directly without going through the standard page table
allocation routines (such as pte_alloc_one_kernel()) when the CPA code
splits a large page (__split_large_page()).
This means the page table constructor is never called nor is the page table
marked as a kernel page table.
The former results in the folio associated with the page table not being
marked as a page table (__pagetable_ctor() is never called thus neither is
__folio_set_pgtable()) nor are statistics updated to reflect
it (lruvec_stat_add_folio() is never called).
The latter issue of failing to mark the page table as a kernel page
table (ptdesc_set_kernel() is never called) is far more problematic.
Since commit:
5ba2f0a15564 ("mm: introduce deferred freeing for kernel page tables")
kernel page table freeing has been batched and since the
subsequent commit:
e37d5a2d60a3 ("iommu/sva: invalidate stale IOTLB entries for kernel address space")
IOTLB cache entries for kernel page tables have been invalidated upon
being freed.
Since split page tables are freed without this invalidation, the IOTLB
can contain stale entries for them.
Resolve the issue by using the ordinary PTE allocation API at split time.
This results in these kernel page tables invoking a page table constructor,
and thus requires a page table destructor.
Destructors are not always present, like for early allocated direct map
page tables). Conditionally call pagetable_dtor_free() if the PG_table
folio flag for the ptdesc is set, otherwise we free the page table via
pagetable_free().
Regardless of which path is taken page tables marked as kernel page tables,
which now includes split page tables, take the correct route through
pagetable_free_kernel().
There is a user-visible side effect in that split page tables will appear
in nr_page_table_pages in /proc/vmstat (as do other kernel page tables
allocated after early boot), however this is a positive change.
This issue started being markedly problematic after commit:
5ba2f0a15564 ("mm: introduce deferred freeing for kernel page tables")
so choose this as the Fixes target.
[ dhansen: rephrase in imperative mood ]
Fixes: 5ba2f0a15564 ("mm: introduce deferred freeing for kernel page tables")
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Vishal Moola <vishal.moola@gmail.com>
Tested-by: Atish Patra <atishp@meta.com>
Tested-by: Nikunj A Dadhania <nikunj@amd.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260813-cpa-fixes-v2-4-39b4ff90f91d@kernel.org
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A previous commit protected against races between ptdump and CPA collapse,
however one still exists between attribute changes and collapse as reported
by Denis V. Lunev (linked).
When an attribute change arises, a lockless page table walker obtains a PTE
entry, which is later written to via set_pte_atomic():
...
-> change_page_attr_set_clr()
-> __change_page_attr_set_clr()
-> __change_page_attr()
-> _lookup_address_cpa()
-> lookup_address_in_pgd_attr()
-> [ lockless page table walker ]
-> set_pte_atomic()
There is nothing preventing a concurrent CPA collapse which can free the
PTE that was retrieved here, resulting in a use-after-free.
With the mmap write lock taken on init_mm over CPA collapse, resolve this
race by acquiring an mmap read lock on init_mm over
__change_page_attr_set_clr().
This locks across the whole operation over which the walk and the PTE
entry write occurs, solving the race.
It is safe to do this here, as no spinlocks are held upon entry to
__change_page_attr_set_clr().
However, the lock must not be held over an allocation, as allocation can
trigger reclaim and shrinkers may call into CPA recursively, making
deadlocks possible (init_mm -> ... -> fs_reclaim -> init_mm).
A page table is allocated when a huge page needs to be split:
-> change_page_attr_set_clr()
-> __change_page_attr_set_clr()
-> __change_page_attr()
-> split_large_page()
[ pagetable_alloc() ]
-> __split_large_page()
Avoid deadlocks by dropping the mmap lock across pagetable_alloc() in
split_large_page() and track whether this is needed by adding a new
'init_mm_read_locked' flag to struct cpa_data.
This is safe as __split_large_page() (called with locks re-established)
revalidates that the page table entry is the same as it was prior to the
locks being dropped and __change_page_attr() repeats the entire page table
walk whenever a split occurs, so concurrent split and collapse are
accounted for.
Concurrent ptdump is also safe as the lock is only dropped over page table
allocation during which time the page table has not yet been modified.
The CPA_COLLAPSE flag is only set by set_memory_rox(), which exclusively
operates upon vmalloc ranges, and on x86 only within the module mapping
space.
This is important, because some callers directly invoke
__change_page_attr_set_clr(), bypassing this lock. However, none of these
operate within the module mapping space.
* cpa_process_alias() - a recursive helper called by
__change_page_attr_set_clr().
* __set_memory_enc_pgtable() - operates on the direct mapping and (via
__vmbus_establish_gpadl()) the vmalloc mapping space.
* __set_pages_[n]p() - called by set_direct_map_[invalid, default,
valid]_noflush(), __kernel_map_pages() - operates on the direct map.
* kernel_[un]map_pages_in_pgd() - operates on EFI ranges.
This work is based upon Denis V. Lunev's excellent analysis of the bug
with gratitude.
[ dhansen: move to imperative voice in changelog ]
Fixes: 41d88484c71c ("x86/mm/pat: restore large ROX pages after fragmentation")
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Atish Patra <atishp@meta.com>
Tested-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/all/20260626163213.2284080-1-den@openvz.org/
Cc:stable@vger.kernel.org
Link: https://patch.msgid.link/20260813-cpa-fixes-v2-2-39b4ff90f91d@kernel.org
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x86 implements page attribute modification using its Change Page
Attributes (CPA) mechanism.
This tracks properties of ranges such as cache mode through x86 page
attributes, and as part of that logic manipulates kernel page tables.
Since commit:
41d88484c71c ("x86/mm/pat: restore large ROX pages after fragmentation")
ranges of kernel page table entries can be collapsed into
huge page table entries as part of this logic.
As part of this collapse, it frees the page tables which the collapsed
entries previously pointed to, and it does so without any relevant locks
being held to preclude concurrent kernel page table walkers.
The only way this code can be reached is if CPA_COLLAPSE is specified, and
this is only set in set_memory_rox() via:
set_memory_rox()
-> change_page_attr_set_clr()
-> cpa_flush()
-> cpa_collapse_large_pages()
Notable users of this are execmem and BPF when manipulating executable
mappings.
However, this is problematic for ptdump as it walks ranges it does not own
and thus runs the risk of a use-after-free on page tables freed underneath
it.
In addition, concurrent CPA collapse operations are possible which can also
cause races.
Resolve the issue by acquiring the mmap write lock on init_mm across the
whole operation.
It is safe to acquire a sleeping lock as all the callers invoke
set_memory_rox() from process context and in any case,
change_page_attr_set_clr() calls vm_unmap_alias() which ultimately takes a
mutex, disallowing atomic context here.
Fixes: 41d88484c71c ("x86/mm/pat: restore large ROX pages after fragmentation")
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Will Deacon <will@kernel.org>
Reviewed-by: David Carlier <devnexen@gmail.com>
Tested-by: Atish Patra <atishp@meta.com>
Tested-by: Nikunj A Dadhania <nikunj@amd.com>
Cc:stable@vger.kernel.org
Link: https://patch.msgid.link/20260813-cpa-fixes-v2-1-39b4ff90f91d@kernel.org
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Pull MM updates from Andrew Morton:
- "mm: drop "sub" prefix from various places" (Dev Jain)
page->folio conversion and a naming cleanup
- "mm/kasan: remove redundant initialization for kasan_flag_write_only"
(Igor Putko)
KASAN cleanup work
- "mm/filemap: reduce unnecessary xarray lookups" (Chi Zhiling)
Small speedup in the pagecaache read code
- "mm/percpu: Fix possible NOFS/NOIO reclaim recursion" (Kaitao Cheng)
Improve the vmalloc code - mainly the avoidance of GFP_KERNEL
allocations when the caller asked for GFP_NOFS or GFP_NOIO
- "mm/kmemleak: avoid soft lockup when scanning task stacks" (Breno
Leitao)
Avoid a soft lockup watchdog trigger from the kmemleak scanning code
in extreme situations
- "mm/page_owner: misc cleanups" (Ye Liu)
Cleanups to the page_owner code. For some reason lots of people have
been working on the page_owner code this cycle.
- "mm: convert to walk_page_range_vma() to eliminate find_vma()"
(Kefeng Wang)
Simplify and accelerate the page walking library function
- "mm/migrate: preparatory cleanups for batch copy and offload"
(Shivank Garg)
Cleanups in the migration code
- "mm/page_owner: add per-fd filter infrastructure for print_mode and
NUMA filtering" (Zhen Ni)
Per-fd filtering to page_owner in order to reduce the sometimes vast
amount of output it can produce
- "mm: Refactor bootmem gigantic hugepage allocation" (Muchun Song)
Fixes and preparatory cleanups around bootmem HugeTLB handling,
sparse initialization ordering, and related vmemmap setup
- "mm/zsmalloc: reduce lock contention in zs_free()" (Wenchao Hao)
Reduce lock contention in zs_free(), which dominates the unmap path
under memory pressure on Android (LMK kills) and on x86 servers
running zswap-heavy workloads.
Up to 1.83x improvement in microbenchmarking.
- "move alloc_tag.c file under mm/" (Suren Baghdasaryan)
- "samples/damon: handle damon_{start,stop}() failures" (SJ Park)
Fix improper handling of damon_start(), damon_stop(), and
damon_call() failures across DAMON sample modules to prevent
potential memory leaks, operation disruptions and use-after-free
bugs
- "mm/damon/sysfs: kobject_del() directories that users can
create/remove" (SJ Park)
Fix delayed sysfs directory removal under DEBUG_KOBJECT_RELEASE
causeing creation failures due to duplicate directory names by adding
missing kobject_del() calls before creating new directories
- "mm: cleanup clear_not_present_full_ptes()" (David Hildenbrand)
Clean up the core pte handling code
- "selftests/damon: misc fixes for test bugs" (Kunwu Chan)
Fix several bugs in the DAMON selftests
- "selftests/damon: fix memcg_path staging handling" (Cheng Nie)
Fix a bug in _damon_sysfs.py for damos_filter memcg_path setup, and
add a test case for it in sysfs.py.
- "selftests/damon: test kdamond refresh_ms" (Ruslan Valiyev)
Selftest coverage for DAMON's refresh_ms sysfs feature by updating
the test control module and verifying that scheme stats update
automatically without manual intervention
- "mm/damon: five misc fixups" (Akinobu Mita)
Miscellaneous DAMON fixups.
- "mm/damon/core: detect internal variation above max_nr_regions/2"
(Jiayuan Chen)
Fix DAMON's region splitting behavior when region counts exceed half
the maximum budget by dynamically scaling down the split fraction as
the limit approaches, preventing large regions from staying un-split,
and add corresponding KUnit test coverage
- "mm: preparatory patches for PMD level swap entries" (Usama Arif)
Refactor and clean up PMD softleaf helpers, call sites, and
architecture flags to lay the groundwork for a follow-up series that
introduces PMD page table swap entries
- "mm/damon: update, optimize, and clean up doc, tests, and code" (SJ
Park)
Update DAMON design and ABI documentation, expands unit and selftest
coverage, optimize damon_commit_target_regions(), and clean up
recently added sysfs interface code for better readability
- "mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2"
(Usama Arif)
Optimize vmpressure() by skipping unnecessary work on cgroup v2 for
userspace event notifications and refactor v1-only eventfd handling
into mm/memcontrol-v1.c to reduce memory overhead and code complexity
- "selftests/mm: refactor pkey helpers and fix mmap error handling"
(Hongfu Li)
Refactor pkeys shared tracing and assertion helpers into a common
file, unify protection key selftests to use consistent diagnostic
logging and assertions, and enforce standardized MAP_FAILED return
checks for mmap() calls across the tests
- "mm/damon: optimize out nr_accesses_bp" (SJ Park)
Replace the error-prone, continuously updated nr_accesses_bp field in
damon_region with an on-demand moving sum function, reducing
structure memory overhead and avoiding state corruption bugs
- "Open HugeTLB allocation routine for more generic use" (Ackerley Tng)
Decouple HugeTLB folio allocation from VMA dependencies by
introducing hugetlb_alloc_folio(), enabling subsystems like
guest_memfd to allocate HugeTLB folios without standard VMA
reservations or pseudo-VMAs
- "mm/damon: provide pseudo moving sum probe_hits" (SJ Park)
Integrate DAMON's probe_hits attribute counter into the pseudo moving
sum infrastructure, enabling real-time, online monitoring without
waiting for full aggregation intervals
- "mm: Some cleanups for page allocator APIs" (Brendan Jackman)
Simplify and refactor the page allocator entry points and flags by
unifying allocation paths, adding internal alloc_flags arguments, and
eliminating redundant __ prefixed alloc_pages variants.
- "Fix incorrect access of hugetlb pte entries" (Dev Jain)
Enforce the consistent use of huge_ptep_get() instead of ptep_get()
for HugeTLB entries and fixes an unaligned address issue in arm64's
huge_ptep_get() implementation
- "mm/damon: validate all parameters in the core" (SJ Park)
Consolidate parameter validation into the DAMON core specifically
within damon_start() and damon_commit_ctx() to centralize error
checking, eliminate caller-side redundant checks and to improve
maintenance efficiency
- "tools/mm/page_owner_sort: fix filtering and cleanup issues" (Yichong
Chen)
Rename is_need() to filter_record() for clearer return semantics, fix
per-record allocation memory leaks and bound output copies in
search_pattern() to address an existing buffer issue
- "memcg: bail out reclaim when memcg is dying" (Jiayuan Chen)
Mitigate a system-wide stall which occurs when a cgroup is removed
while one of its memory control files is doing synchronous reclaim
- "mm/memory-failure: add panic option for unrecoverable pages" (Breno
Leitao)
Introduce an opt-in vm.panic_on_unrecoverable_memory_failure sysctl
that immediately panics the kernel on unrecoverable memory errors in
kernel-owned pages to preserve error context and prevent delayed,
silent data corruption
- "mm/damon: refactor damon_{start,stop,commit}() for simple error
handling" (SJ Park)
Refactor the DAMON core API functions to guarantee that all contexts
are fully stopped when damon_start(), damon_stop(), or damon_commit()
fail, eliminating the need for complex and error-prone caller-side
cleanup code
- "Keep tail page private zero at free and folio split" (Zi Yan)
Add checks to ensure tail_page->private is zero when freeing compound
or high-order pages and when promoting tail pages during large folio
splits. By validating these fields at free and split time, it allows
the removal of redundant private field clearing inside
prep_compound_tail()
- "mm: drop redundant lru_add_drain in anon folio reuse paths" (Barry
Song)
Eliminate redundant lru_add_drain() calls in
wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock
contention and system overhead
By validating folio refcounts against the LRU cache before draining
and removing unnecessary drains in the swap path, it achieves up to a
30.5% reduction in drain calls during heavy swap workloads
- "mm: clean up folio LRU and swap declarations" (Jianyue Wu)
Reorganize folio LRU and swap code by relocating page-cluster state
to mm/swap_state.c, renaming mm/swap.c to mm/folio.c, and moving
MM-internal reclaim declarations into mm/internal.h.
- "userfaultfd: working set tracking for VM guest memory" (Kiryl
Shutsemau)
Add userfaultfd support for tracking the working set of VM guest
memory, so a VMM can identify hot pages and reclaim cold ones to
tiered or remote storage
- "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)" (David
Hildenbrand)
Remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE,
performing some smaller cleanups around freeing of reserved vmemmap
pages on the way.
- "mm/damon: update probe hits for runtime parameter commits" (SJ Park)
Ensure that DAMON's probe_hits attribute counter is properly updated
when monitoring intervals are changed at runtime, matching the
behavior of nr_accesses. To achieve this, it refactors and renames
existing helper functions for shared use, applies the updates to
probe_hits, and handles edge cases in damon_probe_hits_mvsum() to
maintain measurement accuracy.
- "KSM: performance optimizations for rmap_walk_ksm" (xu xin)
Resolve a severe KSM reverse-mapping performance bottleneck where
thousands of split VMAs sharing a single anon_vma cause extended lock
contention.
By adding an interval-filtering check during the rmap walk, it
reduces worst-case anon_vma lock hold times from over 500ms down to
under 2ms, preventing application freezes and latency spikes under
memory pressure.
- "mm: split a couple of headers from internal.h" (Mike Rapoport)
Split declarations related to mm_init, memblock, vmalloc and sparse
into new headers
- "KSM: use linear_page_index in collect_procs_ksm()" (xu xin)
Apply the interval tree optimization from rmap_walk_ksm() to
collect_procs_ksm() to avoid iterating over non-matching VMAs during
KSM memory error handling.
It hoists loop-invariant address initialization and restricts the
anon_vma_interval_tree_foreach walk to a targeted page offset range,
reducing redundant checks and improving lookup efficiency.
- "selftests/mm: avoid false failures in hugetlb and KSM tests" (Sayali
Patil)
Fix issues in the hugetlb and KSM MM selftest categories that can
report failures when the prerequisites for the tests are not
satisfied
- "mm/damon: introduce data attributes only monitoring" (SJ Park)
Introduce attribute-weighted region management in DAMON, allowing
users to prioritize specific data attributes (such as page sizes or
cgroups) over or instead of access monitoring.
By assigning weights to attribute probes, DAMON can completely
disable access tracking and adjust monitoring regions based on
weighted probe-hit counters to optimize monitoring quality for
attribute-focused workloads.
- "mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings"
(Stanislav Kinsburskii)
Extend hmm_range_fault() to support userfaultfd-backed regions by
allowing the mmap lock to be dropped during fault handling via a new
hmm_range_fault_locked() helper.
By accepting a locked pointer and signaling retry status when lock
release occurs, it enables page fault resolution in userfaultfd
regions while preserving backward compatibility for existing callers.
- "mm: make VMA page offset handling more consistent" (Lorenzo Stoakes)
Clean up and standardize how vma->vm_pgoff is accessed and
manipulated across file-backed and anonymous mappings in the kernel
It introduces dedicated helper functions such as vma_start_pgoff(),
vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while
renaming rmap interval tree helpers to better reflect their
functionality.
These changes establish a cleaner foundation for future work that
will unify virtual page offset indexing for all anonymous and CoW'd
folios.
- "mm: handle device-private PMDs in walk callbacks" (Usama Arif)
Address kernel panics and state corruption caused by MM walk
callbacks reaching non-present device-private PMD swap entries
created during HMM migrations
It ensures that functions which acquire pmd_trans_huge_lock()
properly recognize device-private PMDs instead of assuming a present
THP or a standard migration entry.
- "mm/rmap: Refactor try_to_unmap_one" (Dev Jain)
Refactor try_to_unmap_one by modularizing Hugetlb,
anonymous-lazyfree, and anonymous-swapbacked logic into dedicated
functions, laying the structural groundwork for batched anonymous
large folio unmapping.
- "Docs/ABI/damon: sysfs ABI document fixes and additions" (Song Hu)
Fix typos and fills in missing entries in the DAMON sysfs ABI
document
- "dax/kmem: atomic whole-device hotplug via sysfs" (Gregory Price)
Introduce an atomic sysfs state attribute and supporting DAX/MM
infrastructure to prevent userland races when offlining and removing
entire memory regions
By adding an unplugged state alongside standard online modes, it
enables whole-device atomic hotplug control while preserving backward
compatibility.
- "mm: convert more vm_flags_t users to vma_flags_t" (Lorenzo Stoakes)
Continue transitioning the kernel from the deprecated vm_flags_t type
to vma_flags_t across core memory management infrastructure.
It replaces legacy type usage in core functions such as do_mmap(),
unmapped area allocation, mm->def_vma_flags, and VMA operations like
mlock, mprotect, and mremap.
- "Two small patches to clean up mm/mm_slot.h" (xu xin)
Refactor mm_slot.h by introducing mm_slot_remove() to unify duplicate
slot deletion sequences in khugepaged and KSM. It also adds code
documentation explaining why mm_slot_lookup and mm_slot_insert must
remain as preprocessor macros rather than static inline functions.
- "mm/damon/core: hide core-private struct fields" (SJ Park)
Clean up DAMON core structures by consistently marking internal-only
fields with private: comment tags to prevent improper direct access
from outer layers.
It enforces encapsulation across core structures including
damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to
interact through approved access APIs instead of exposing raw struct
members.
- "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races"
(SJ Park)
Address potential infinite loops, NULL dereferences, and race
conditions identified in DAMON
It fixes an infinite loop triggered by extreme user configurations, a
NULL pointer dereference within unit tests and minor monitoring
accuracy degradation caused by subtle runtime races.
- "mm/page_alloc: fixes for free_pages_nolock() on RT/UP" (Brendan
Jackman)
Fix an NMI safety flaw in __free_frozen_pages() where freeing pages
on non-SMP or PREEMPT_RT kernels can bypass can_spin_trylock() checks
via non-PCP or isolated migration paths.
It also resolves potential kernel crashes and privilege escalation
risks triggered when BPF tracing runs in NMI context alongside memory
hotplug or large allocation frees.
- "mm/page_alloc: couple of followups for recent cleanups" (Brendan
Jackman)
Clean up and update page allocator nomenclature, documentation, and
debug assertions.
It aligns internal FPI_ flags with the public "nolock" naming
convention, removes outdated internal implementation details from
high-level page allocator comments, and eliminates obsolete
VM_BUG_ON() assertions in allocation paths.
- "mm/mseal: further cleanups" (Lorenzo Stoakes)
Refactor and simplify the mseal implementation by clarifying API
boundaries and removing unnecessary code complexity.
It replaces generic do_mseal() usage outside the syscall with a
dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO,
eliminates mm_struct parameters to enforce that sealing applies only
to current->mm, and streamlines overall logic and comments with no
functional changes intended.
- "mm/vmscan: fix swappiness=max and clean up per-node proactive
reclaim" (Ridong Chen)
Resolve reclaim behavior bugs and clean up function parameters across
memory reclaim paths
It fixes swappiness=max in both standard reclaim and MGLRU so
unswappable anonymous memory no longer falls back to evicting page
cache, ensures reclaim_store() returns accurate error codes instead
of collapsing all failures into -EAGAIN, and removes the obsolete
gfp_mask parameter from __node_reclaim().
- "mm: mincore: misc cleanups" (Kefeng Wang)
Clean up and simplifies the mincore code. Most importantly, it
removes the historical special behavior that always reports VM_PFNMAP
pages as non-resident.
- "mm/huge_memory: drop dead split helper variants" (Kiryl Shutsemau)
Two trivial cleanups in the folio split API
- "mm/damon: fix uninitialized DAMOS field and kunit exec expectation
bugs" (SJ Park)
Resolve minor operational and testing bugs in DAMON identified by
Sashiko. It initializes the damos->last_applied field to prevent
occasional efficiency degradation and fixes invalid memory accesses
in DAMON KUnit tests during test failure handling.
- "cleanup for stable_page_flags()" (Jinjiang Tu)
Clean up and refactor stable_page_flags() used by /proc/kpageflags
without altering functionality.
It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag
bits, converts folio-specific flag checks to standard folio_test_*()
helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling.
- "Batch unmap of uffd-wp file folios" (Dev Jain)
Extend batched folio unmapping support to file folios within
userfaultfd write-protect (uffd-wp) VMAs by adding batching
capabilities to pte_install_uffd_wp_if_needed().
This removes special-case restrictions on uffd-wp VMAs in
try_to_unmap_one(), significantly simplifying the function's control
flow and complexity.
- "mm/early_ioremap: clarify and clean up early_ioremap_reset()"
(Sang-Heon Jeon)
Clarify and clean up the architecture-specific usage of
__late_set_fixmap() and __late_clear_fixmap() after
early_ioremap_reset()
It adds explicit documentation regarding when early_ioremap_reset()
must be called and removes redundant macro definitions and reset
calls in the RISC-V and ARM64 architectures.
- "mm: fix reclaim storms in defrag_mode" (Johannes Weiner)
Address severe performance regressions, swap storms, and spurious
OOMs caused by vm.defrag_mode=1 under high memory pressure in Meta
production
It updates the page allocator slowpath so non-movable allocation
requests actively trigger direct reclaim and direct compaction at
pageblock_order scale, allowing them to claim whole pageblocks rather
than spinning unproductively.
- "zram: lockmap tweaks" (Sebastian Siewior)
Optimize and fix lockdep tracking for zram devices by consolidating
per-entry lockmaps and isolate lock classes across multiple instances
This reduces memory overhead by replacing per-entry lockdep_map
instances with a single map per struct zram, and assigns a dynamic
lock_class_key to each instance to prevent false deadlock reports
when different zram devices are backed by distinct filesystems.
* tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (501 commits)
selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check
selftests/mm: unpoison pages in memory-failure teardown
mm/shmem: downgrade final i_blocks check in shmem_evict_inode() to pr_warn()
mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro
mm/zsmalloc: fix release order of locks in zs_page_migrate()
Documentation: zram: remove sections numbering
ksm: stop iterating VMAs when ksm_test_exit returns true
mm: fold userfaultfd_rwp() to false without CONFIG_ARCH_HAS_PTE_PROTNONE
mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
zram: use a custom key for each zram object
zram: move lockmap to be per-zram instead per table
selftests/mm: fix gup_longterm EINVAL error message
mm: page_alloc: fix non-movable reclaim storm in defrag_mode
mm: page_alloc: move capture_control to the page allocator
mm: compaction: support non-movable compaction for pageblock requests
mm: page_alloc: __GFP_FS lockdep annotation for direct compaction
hugetlb: evaluate subpool free state while locked
mm/damon: remove trailing semicolons after function definitions
mm/damon/ops-common: prevent migration fallback to non-target nodes
mm/damon: update outdated comment about DAMOS filter handling
...
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Pull bpf updates from Daniel Borkmann:
"Major changes:
- Redesign the verifier error reporting: failures now carry source
and instruction annotations along with the causal event history
that led to them, making program rejections far easier to debug and
repair (Kumar Kartikeya Dwivedi)
- Add arena argument support to kfuncs and struct_ops through the new
__arena and __arena__nullable suffixes (Tejun Heo, Puranjay Mohan,
Kumar Kartikeya Dwivedi, Ihor Solodrai)
- Signed BPF program loader rework to accommodate both BPF and
security community needs where the kernel runs the signature
verification at BPF_PROG_LOAD time before the LSM admission hook
(Daniel Borkmann)
- Add a set of ksock kfuncs which let BPF LSM and syscall programs
create, connect and send on UDP sockets in order to emit telemetry
data (Mahe Tardy)
- Unify helper and kfunc call argument verification and classify
kfunc arguments purely from BTF into a generated bpf_func_proto
which is computed once at add-call time (Amery Hung)
Other features and fixes:
- Enable EXECMEM_ROX_CACHE for BPF allocations on x86 (Mike Rapoport)
- Add bidirectional VLAN support to bpf_fib_lookup() through the new
BPF_FIB_LOOKUP_VLAN and BPF_FIB_LOOKUP_VLAN_INPUT flags (Avinash
Duduskar)
- Infer zext_dst from static register liveness analysis to fix 32-bit
zero-extension semantics, and remove the artificial limitations on
pointer types eligible for spilling (Eduard Zingerman)
- Inline the numeric open-coded iterator kfuncs so that bpf_for()
loops no longer pay a kfunc call on every iteration (Puranjay
Mohan)
- Add an arena-based bitmap data structure to libarena along with
serial and parallel selftests (Emil Tsalapatis)
- Teach resolve_btfids to discover kfuncs from the kernel's BTF ID
sets and to emit kfunc BTF decl tags, reducing the kernel build's
dependency on pahole features (Ihor Solodrai)
- Add BPF_F_ADJ_ROOM_DECAP_* flags to bpf_skb_adjust_room() so that
tunnel decapsulation can update the GSO and encapsulation state of
the skb (Nick Hudson)
- Fix the ring buffer pending_pos walk and the available-data
accounting on 32-bit position wrap (Israel Téllez García)
- Add memory usage accounting for arena maps and fix an mmap_lock
deadlock on arena lock failure (Jiayuan Chen)
- Add tracing_multi link info support to the kernel UAPI and bpftool,
and refactor the stack map code to run with preemption disabled
(Jiri Olsa)
- Support BPF_F_EGRESS in bpf_redirect_peer() to emit the skb in the
egress direction of the target's peer device (Jordan Rife)
- Add a KF_SPINLOCK_SAFE kfunc flag so that providers, in particular
modules, can declare kfuncs safe to call under bpf_spin_lock
instead of relying on the verifier's hard-coded allowlist (Kaitao
Cheng)
- Introduce global percpu data for BPF programs with libbpf probing
and bpftool skeleton support, and stop exposing uninitialized
kernel heap memory when copying per-CPU map values (Leon Hwang)
- Add s390 JIT support for load-acquire and store-release
instructions (Maxim Khmelevskii)
- Fix a CFI mismatch in the task work callback and an arm64 KASAN
false positive after bpf_throw() (Mykyta Yatsenko)
- Reject writes through untrusted BTF pointers and bound the
rdonly/rdwr_buf_size kfunc arguments (Nicholas Dudar)
- Invalidate RCU pointers only after the final spin unlock and
account for preempt and IRQ disabled regions as overlapping RCU
protection (Ning Ding)
- Support mixing bpf2bpf calls and tail calls on RV64, add signed
operations and 32-bit atomics to the RV32 JIT, and add timed
may_goto support (Pu Lehui, Kuan-Wei Chiu, Feng Jiang)
- Fix a use-after-free on mm_struct in bpf_find_vma() for foreign
tasks and an mmap_lock leak in the irq_work path (Sanghyun Park)
- Populate mmap-able BPF array map memory lazily which makes mmap()
O(1) instead of proportional to the map size (Song Liu)
- Introduce a jit_required flag and reject programs with inlined
helpers when no JIT is available, where the interpreter would
otherwise jump into an invalid address (Tiezhu Yang)
- Fix the x86 JIT per-CPU address resolution into an extended
register where the REX prefix dropped the high destination register
bit (Vineet Gupta)
- Reject MEM_ALLOC BTF accesses past object bounds, arena frees below
the arena base, and mixed arena and ordinary atomic paths (Yiyang
Chen)
- Fix the trampoline handling of 128-bit arguments and of return
values larger than 8 bytes (Yonghong Song)
- Ensure that any fault prone load is rewritten with exception table
handling, and fix the arena load-acquire and atomic fetch handling
in the x86, arm64, riscv and s390 JITs (Daniel Borkmann)
- Many more fixes and cleanups across the verifier, arena,
trampolines, sockmap, cgroup, ring buffer, x86/arm64/riscv/s390
JITs, libbpf, bpftool, resolve_btfids and selftests"
* tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (373 commits)
selftests/bpf: Add tests for a store on a fault prone qdisc pointer
selftests/bpf: Add tests for fault prone loads out of RCU pointers
selftests/bpf: Add tests for pointer type merge at a shared load
selftests/bpf: Remove duplicate copies of the arena spinlock qnodes
selftests/bpf: Retry stat generation in cgroup_iter_memcg
selftests/bpf: Test pseudo-function policy diagnostics
bpf: Distinguish function references in policy diagnostics
bpf: Preserve source attribution without source text
selftests/bpf: Test kfunc argument diagnostics
bpf: Correct kfunc argument diagnostics
bpf: Use canonical stack argument names in diagnostics
bpf: Preserve R0 lineage across helper calls
selftests/bpf: Exercise negative optlen in cgroup getsockopt hook
bpf: Reject negative optlen in cgroup getsockopt hook
selftests/bpf: tc_tunnel - validate decap GSO and encapsulation state
bpf: Clear decap state on skb_adjust_room shrink path
bpf: Allow new DECAP flags and add guard rails
bpf: Add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation
bpf: Refactor masks for ADJ_ROOM flags and encap validation
bpf: Name the enum for BPF_FUNC_skb_adjust_room flags
...
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Pull x86 cpuid updates from Borislav Petkov:
- Get rid of static_cpu_has() - one less API to care about testing CPU
features
- Unify the handling of CPU core types (performance, efficient, etc) by
mapping the vendor-specific types to Linux ones
- Continuation of the work of Ahmed Darwish to centralize CPUID leaf
representation
* tag 'x86_cpu_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU: Rename struct cpuid_read_output to struct cpuid_output
x86/cpu/scattered: Sort it properly
x86/cpu: Use parsed CPUID(0x1)
x86/lib: Add CPUID(0x1) family and model calculation
x86/cpu: Use parsed CPUID(0x0)
x86/cpu/transmeta: Rescan CPUID(0x1) after modifying capabilities
x86/topology: Add TOPO_CPU_TYPE_LOW_POWER
x86/topology: Name the AMD core-type values
x86/topo: Map vendor CPU types to generic Linux such types
x86/bugs: Don't use cpu-type matching in cpu_vuln_blacklist
x86/cpu: Hide and rename static_cpu_has()
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Pull x86 cleanups from Borislav Petkov:
- The usual pile of smallish cleanups and fixlets all over the place
* tag 'x86_cleanups_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Remove unnecessary __maybe_unused annotations
x86/msr: Document the I/O-like write semantics in the msr driver
x86/apic: Ensure ICR register write value is handled as 32 bits
x86/boot/compressed/head_64.S: Clean up SEV-related comments
Documentation/arch/x86/amd-memory-encryption.rst: Fix typo
x86/platform/quark: Fix kernel-doc warnings in imr.c
x86/ras: Move contents from arch/x86/ras/Kconfig into drivers/ras/Kconfig
x86/cpu: Move intel_get_platform_id() to cpu/intel.c
x86/mm: Fix typo in comment
x86/fpu: Fix kernel-doc formatting above fpu_enable_guest_xfd_features()
x86/cfi: Use symmetric SYM_START and SYM_END in __CFI_TYPE()
x86/cfi: Add __init_or_module annotations for fineibt
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Pull x86 mm updates from Dave Hansen:
"There are two things in here of note. First, there are fixes to reduce
the time that the TLB flushing code sits around with interrupts
disabled. It should be well tested, but it's certainly something to
keep an eye on.
Second is a little back-and-forth in the interactions between the
set_memory*() locking and DEBUG_PAGEALLOC. There was a slightly
painful re-discovery of why DEBUG_PAGEALLOC has special locking rules,
but the code did end up better for it.
Summary:
- Fix pkey_alloc() return value when pkeys are not supported
- Allow preemption during IPI completion waiting to improve wakeup
latency
- Convert more x86 page table code to ptdescs
- Fixes and cleanups for set_memory*() locking, mostly around large
pages"
* tag 'x86_mm_for_7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pkeys: Fix pkey_alloc() return value when pkeys are not supported
x86/mm: Fix and document DEBUG_PAGEALLOC
x86/mm: Use guard() for pgd_lock
x86/mm: Use guard() in cpa_collapse_large_pages()
x86/mm: Re-enable preemption before flush_tlb_multi()
x86/kvm: Disable preemption in kvm_flush_tlb_multi()
x86/mm: Move flush_tlb_info back to the stack
x86/mm: Cap flush_tlb_info alignment at 64 bytes
x86/mm: Factor out flush_tlb_info initialization
x86/mm/pat: Take cpa_lock around large-page collapse
x86/mm/pat: Don't gate cpa_lock on debug_pagealloc_enabled()
x86/xen: Convert xen_mm_unpin_all() to ptdescs
x86/xen: Convert xen_mm_pin_all() to ptdescs
x86/mm: Convert pgd_page_get_mm() to ptdescs
x86/mm: Convert sync_global_pgds_l4() to ptdescs
x86/mm: Convert sync_global_pgds_l5() to ptdescs
x86/mm: Convert arch_sync_kernel_mappings() to ptdescs
x86/mm/pat: Convert collapse_pmd_page() to ptdescs
x86/mm/pat: Convert __set_pmd_pte() to ptdescs
x86/mm/pat: Use IS_ENABLED() instead of ifdef
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It turns out that commit 5fce67641a3e ("x86/mm/pat: Don't gate
cpa_lock on debug_pagealloc_enabled()") was a little too quick to
remove the debug_pagealloc exception for cpa_lock.
Notably __kernel_map_pages() is used by the page-allocator from any
context the page-allocator itself is used, which violates the cpa_lock
rules.
Re-instate the exception, except make it specific to the
__kernel_map_pages() such that any other cpa() usage is still fully
serialized by cpa_lock. Also note that since cpa() should not be used
on memory that isn't allocated, the page-allocator locking and cpa are
infact mutually exclusive and all cpa usage in fully serialized.
Add a comment explaining this and other 'funnies' surrounding
DEBUG_PAGEALLOC, including how pgd_lock is not affected and the TLB
trickery.
Fixes: 5fce67641a3e ("x86/mm/pat: Don't gate cpa_lock on debug_pagealloc_enabled()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260729111119.604452135@infradead.org
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260729111119.488154104@infradead.org
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260729111119.375614011@infradead.org
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CONFIG_HAVE_BOOTMEM_INFO_NODE now essentially doesn't do anything.
So let's remove support for CONFIG_HAVE_BOOTMEM_INFO_NODE.
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-7-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is no good reason to mark boot page tables as MIX_SECTION_INFO: we
only free boot page tables when they are completely empty, and memory
offlining/hotunplug doesn't benefit from it in any way.
So just stop marking page tables as MIX_SECTION_INFO. In
free_pagetable(), we can now simply free reserved pages directly.
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-6-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We added the whole bootmem registration machinery in commit 04753278769f
("memory hotplug: register section/node id to free").
The main use case was to remember to which memory section memmap pages
belonged, so the memmap could be handled accordingly when freeing memory.
However, all that machinery is not required anymore: a memory section can
only get offlined if *all* pages can get offlined; and it can only get
unplugged once offline. If some of these pages are unmovable memmap
pages: bad luck, doesn't work. Offlining will fail.
Further, a lot of this machinery was required for pre-vmemmap support.
Now we only support the vmemmap with memory hotplug.
So the whole machinery is useless today. Let's start by removing the last
pieces by first stopping to mark vmemmap pages as SECTION_INFO. In
free_vmemmap_pages(), we can now always just free the reserved pages
directly.
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-5-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's extend free_reserved_page() in page_alloc.c to
free_reserved_pages(), dropping the custom x86 variant. The common-code
variant will consume an order, so adjust the x86 callers accordingly.
Make free_reserved_pages() assume that we are freeing ordinary high-order
pages, just with the special "reserved" flavor. The target use case for
now is freeing vmemmap PMD pages.
Set the refcount directly to 0 (instead of 1) and call
__free_frozen_pages(). Set the page count to 0 before clearing
PG_reserved, so someone checking PG_reserved (and not finding it set) to
then try grabbing a ref would not suddenly have that ref be dropped. That
is arguably cleaner and safer than the old way of doing it.
Add some kerneldoc. Use a single adjust_managed_page_count() call.
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-2-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)", v2.
Let's remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE,
performing some smaller cleanups around freeing of reserved vmemmap pages
on the way.
This patch (of 10):
All callers pass 0, so let's drop the parameter.
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-0-4afc76c73d61@kernel.org
Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-1-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
flush_tlb_mm_range() and arch_tlbbatch_flush() pin the current CPU while
they decide whether the flush can be handled locally or must be sent to
remote CPUs. The CPU pinning is needed for the current CPU number and for
the local TLB flush path, which reads per-CPU TLB state.
The caller does not need to remain pinned while waiting for a remote TLB
flush to complete. After the remote-flush path has been selected,
flush_tlb_info is caller-private stack storage, so the caller no longer
has to stay on the same CPU to protect a shared per-CPU flush_tlb_info
object.
flush_tlb_multi() may also route through x86 PV backends. Those backends
must protect their own CPU-local scratch state instead of relying on the
caller to stay pinned. Hyper-V already does this by disabling interrupts
while using hyperv_pcpu_input_arg, and Xen's multicall path brackets its
per-CPU multicall buffer with xen_mc_batch() and xen_mc_issue().
kvm_flush_tlb_multi() also disables preemption while using __pv_cpu_mask.
Remote TLB flushes may synchronously wait for many CPUs, and the wait can
take tens of milliseconds when remote CPUs have interrupts disabled or
when many CPUs are involved. Keeping preemption disabled for that whole
wait unnecessarily increases scheduling latency on the initiating CPU.
Drop the CPU pinning before calling flush_tlb_multi() in the remote paths
of flush_tlb_mm_range() and arch_tlbbatch_flush(). Keep the local paths
inside the pinned section because they still access this CPU's TLB state.
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260709122933.4021501-15-zhouchuyi@bytedance.com
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flush_tlb_info benefits from cacheline alignment, but using
cacheline-aligned stack storage directly can grow stack usage too much on
configurations with large SMP_CACHE_BYTES values. Commit 515ab7c41306
("x86/mm: Align TLB invalidation info") attempted to align stack storage,
and commit 780e0106d468 ("x86/mm/tlb: Revert "x86/mm: Align TLB
invalidation info"") reverted it because using SMP_CACHE_BYTES led to 320
bytes of stack consumption. Commit 3db6d5a5ecaf ("x86/mm/tlb: Remove
'struct flush_tlb_info' from the stack") moved flush_tlb_info to per-CPU
storage, which avoided the stack growth problem while preserving
cacheline alignment. That was a good fit while the callers kept
preemption disabled for the whole flush operation.
However, a single per-CPU flush_tlb_info also requires all flush_tlb*()
operations to keep preemption disabled while the object is in use, so
that it cannot be overwritten by another flush on the same CPU.
flush_tlb*() may send IPIs to remote CPUs and synchronously wait for all
remote CPUs to complete their local TLB flushes. That wait can take tens
of milliseconds when interrupts are disabled on a remote CPU or when a
large number of remote CPUs are involved.
To shorten the CPU-pinned and preemption-disabled section around those
remote TLB flush waits, move flush_tlb_info back to caller-private stack
storage. The caller then does not have to stay on the same CPU until the
remote flush completes.
The type alignment is capped at 64 bytes. This keeps the alignment
benefit for stack objects without reintroducing the old large-cacheline
stack usage problem.
To evaluate the performance impact, use the following script to reproduce
the microbenchmark mentioned in commit 3db6d5a5ecaf ("x86/mm/tlb: Remove
'struct flush_tlb_info' from the stack"). The test environment is an Ice
Lake system (Intel(R) Xeon(R) Platinum 8336C) with 128 CPUs and 2 NUMA
nodes. During the test, the threads were bound to specific CPUs, and both
pti and mitigations were disabled:
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <unistd.h>
#define NUM_OPS 1000000
#define NUM_THREADS 3
#define NUM_RUNS 5
#define PAGE_SIZE 4096
volatile int stop_threads = 0;
void *busy_wait_thread(void *arg) {
while (!stop_threads) {
__asm__ volatile ("nop");
}
return NULL;
}
long long get_usec() {
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec * 1000000LL + tv.tv_usec;
}
int main() {
pthread_t threads[NUM_THREADS];
char *addr;
int i, r;
addr = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE
| MAP_ANONYMOUS, -1, 0);
if (addr == MAP_FAILED) {
perror("mmap");
exit(1);
}
for (i = 0; i < NUM_THREADS; i++) {
if (pthread_create(&threads[i], NULL, busy_wait_thread, NULL))
exit(1);
}
printf("Running benchmark: %d runs, %d ops each, %d background\n"
"threads\n", NUM_RUNS, NUM_OPS, NUM_THREADS);
for (r = 0; r < NUM_RUNS; r++) {
long long start, end;
start = get_usec();
for (i = 0; i < NUM_OPS; i++) {
addr[0] = 1;
if (madvise(addr, PAGE_SIZE, MADV_DONTNEED)) {
perror("madvise");
exit(1);
}
}
end = get_usec();
double duration = (double)(end - start);
double avg_lat = duration / NUM_OPS;
printf("Run %d: Total time %.2f us, Avg latency %.4f us/op\n",
r + 1, duration, avg_lat);
}
stop_threads = 1;
for (i = 0; i < NUM_THREADS; i++)
pthread_join(threads[i], NULL);
munmap(addr, PAGE_SIZE);
return 0;
}
base on-stack-aligned on-stack-not-aligned
---- --------- -----------
avg (usec/op) 2.5278 2.5261 2.5508
stddev 0.0007 0.0027 0.0023
The benchmark results show that the average latency difference between
the baseline (base) and the properly aligned stack variable
(on-stack-aligned) is within the standard deviation (stddev). This
indicates that the variations are caused by testing noise, and reverting
to a stack variable with proper alignment causes no performance
regression compared to the per-CPU implementation. The unaligned version
(on-stack-not-aligned) shows a minor performance drop. The
CPU-pinned/preemption-disabled section can therefore be shortened without
sacrificing performance.
With caller-private storage there is no shared per-CPU object to protect,
so remove the DEBUG_VM reentrancy counter as well.
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Link: https://patch.msgid.link/20260709122933.4021501-13-zhouchuyi@bytedance.com
|
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get_flush_tlb_info() has two responsibilities: it reserves the per-CPU
flush_tlb_info storage and it initializes the fields that describe the
flush operation. The per-CPU storage also carries the DEBUG_VM
reentrancy check and the matching put_flush_tlb_info() lifetime rules.
Moving flush_tlb_info back to caller-provided storage requires the same
field initialization without tying the caller to the per-CPU object.
Leaving the field setup embedded in get_flush_tlb_info() would either
keep those callers tied to the per-CPU object or duplicate the
initialization logic.
Split the field setup into init_flush_tlb_info(). Keep the per-CPU
storage selection, DEBUG_VM reentrancy check and put_flush_tlb_info()
lifetime rules in get_flush_tlb_info().
No functional change intended.
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260709122933.4021501-11-zhouchuyi@bytedance.com
|
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BPF core and x86 JIT use text poking and temporary writable buffers and
thus can handle ROX memory.
Enable ROX cache for EXECMEM_BPF when configuration and CPU features allow
that.
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20260716-execmem-x86-rox-bpf-v0-v3-5-4e76158c01c5@kernel.org
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
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Loading and unloading modules concurrently on several CPUs on a KASAN
build, with a short delay injected at the CPA page-table lookup to
widen the window, faults within minutes:
BUG: KASAN: use-after-free in __change_page_attr+0x7cc/0x7e0
Write of size 8 at addr ffff888181139718 by task modprobe
...
The buggy address belongs to the physical page:
pfn:0x181139 ... page_type: f2(table)
cpa_collapse_large_pages() rebuilds a leaf PMD from its 4K PTEs and
frees the old PTE-table pages, while __change_page_attr() fetches a
PTE pointer from a lockless lookup_address_in_pgd_attr() and writes
it with set_pte_atomic() only later. When module text is served from
a shared large ROX mapping the two run on the same PMD:
CPU A (module load) CPU B (module finalize)
------------------- -----------------------
execmem_make_temp_rw
set_memory_nx
__change_page_attr
split 2M -> 4K table P
kpte = &P[i] (lockless)
execmem_restore_rox
set_memory_rox (CPA_COLLAPSE)
cpa_collapse_large_pages
rebuild leaf PMD
flush_tlb_all
pagetable_free(P)
set_pte_atomic(kpte, ...)
-> writes into freed P
P is a page-table page (page_type: table), reused at once, so the
write corrupts whatever got the page next: a bad-pte or bad-page
splat, or a fatal fault once P has been turned into read-only text.
The flush_tlb_all() before the free does not close this: its IPI only
serializes against page-table walkers that run with interrupts off
(e.g. GUP-fast); the walk in __change_page_attr() runs with interrupts
on, so nothing stops it from holding a stale pointer into P.
Serialize the collapse - the PMD rebuild, TLB flush and PTE-table
free - under cpa_lock, the same lock __change_page_attr() now takes
unconditionally since commit ("x86/mm/pat: stop gating cpa_lock on
debug_pagealloc_enabled()"), so a concurrent walker can no longer
hold a pointer into a table the collapse is about to free.
Fixes: 41d88484c71c ("x86/mm/pat: restore large ROX pages after fragmentation")
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Link: https://patch.msgid.link/20260715183453.2381141-1-den@openvz.org
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The splitting and merging of kernel page table mappings between small and
large is protected by cpa_lock. The merging is relatively new but the
splitting is ancient.
The splitting has a locking optimization: since DEBUG_PAGEALLOC forces all
mappings to 4k, there are no large pages to split. So the code that *might*
cause a split can just skip the locking (and a few other things).
This is entertaining, but it adds complexity and makes for weird locking
rules. Plus it's all for a debugging feature which makes the kernel super
slow in the first place. Optimizing something which is already super slow
and not used in production is not the best way to spend our complexity
budget.
Stop gating cpa_lock on debug_pagealloc_enabled() to simplify the code
and the locking rules.
[ dhansen: flesh out changelog ]
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://patch.msgid.link/20260715144519.934289-1-rppt@kernel.org
Link: https://lore.kernel.org/all/aab44f08-89f8-47fe-bee4-0ab6b25968c6@intel.com/
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Convert pgd_page_get_mm() to ptdescs. Define struct ptdesc in our
pgtable_types so that our declarations recognize ptdesc as an
appropriate page table type.
Now that all callers are using ptdescs, we can pass in that
ptdesc to get the underlying mm_struct.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-8-vishal.moola@gmail.com
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Convert sync_global_pgds_l4() to ptdescs in preparation for the
eventual splitting of ptdescs from struct page.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-7-vishal.moola@gmail.com
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Convert sync_global_pgds_l5() to ptdescs in preparation for the
eventual splitting of ptdescs from struct page.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-6-vishal.moola@gmail.com
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Convert arch_sync_kernel_mappings() to ptdescs in preparation for
the eventual splitting of ptdescs from struct page.
Following this patch, we can successfully boot a 32-bit x86 kernel with
separately allocated ptdescs.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-5-vishal.moola@gmail.com
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Convert collapse_pmd_page() to ptdescs in preparation for the
eventual splitting of ptdescs from struct page.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-4-vishal.moola@gmail.com
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Convert __set_pmd_pte() to ptdescs in preparation for the eventual
splitting of ptdescs from struct page.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-3-vishal.moola@gmail.com
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Use IS_ENABLED() to check if we are on 32 bit. This standardizes this
check with the other 32 bit check in the file. No functional changes.
Signed-off-by: Vishal Moola <vishal.moola@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260629185742.126987-2-vishal.moola@gmail.com
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cpu_feature_enabled() is the one to use to test feature flags so hide
the static thing which doesn't pay attention to disabled mask bits
anyway.
Use the following command to do the replacement:
$ git grep --files-with-matches -w static_cpu_has -- ':(exclude)*cpufeature.h' \
| xargs sed -i 's/static_cpu_has(/cpu_feature_enabled\(/g'
There should be no functional changes resulting from this.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://patch.msgid.link/20260620015041.336288-1-bp@kernel.org
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numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant. Remove it.
No functional change.
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Link: https://patch.msgid.link/20260703041329.2797584-5-ekffu200098@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
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Fix "begining" to "beginning" in a code comment.
Signed-off-by: You-Li Lin <lhu540507@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260627051343.51326-1-lhu540507@gmail.com
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Pull MM updates from Andrew Morton:
- "selftests/mm: clean up build output and verbosity" (Li Wang)
Remove some noise from the MM selftests build
- "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts)
Speed up the freeing of a batch of 0-order pages by first scanning
them for coalescing opportunities. This is applicable to vfree() and
to the releasing of frozen pages
- "mm/damon: introduce DAMOS failed region quota charge ratio"
(SeongJae Park)
Address a DAMOS usability issue: The DAMOS quota often exhausts
prematurely because it charges for all memory attempted, causing slow
and inconsistent performance when actions fail on unreclaimable
memory.
To fix this, a new feature lets users set a smaller, flexible quota
charge ratio (via a numerator and denominator) for failed regions.
Since failed actions cause less overhead, reducing their quota cost
ensures more predictable and efficient DAMOS processing
- "selftests/cgroup: improve zswap tests robustness and support large
page sizes" (Li Wang)
Fix various spurious failures and improves the overall robustness of
the cgroup zswap selftests
- "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga)
Fix an issue in the mlock selftests on arm32
- "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao)
Some maintenance work in the huge_memory code
- "treewide: fixup gfp_t printks" (Brendan Jackman)
Use the special vprintf() gfp_t conversion in various places
- "mm: Fix vmemmap optimization accounting and initialization" (Muchun
Song)
Fix several bugs in the vmemmap optimization, mainly around incorrect
page accounting and memmap initialization in the DAX and memory
hotplug paths. It also fixes pageblock migratetype initialization and
struct page initialization for ZONE_DEVICE compound pages
- "mm/damon: repost non-hotfix reviewed patches in damon/next tree"
A sprinkle of unrelated minor bugfixes for DAMON
- "mm: remove page_mapped()" (David Hildenbrand)
Remove this function from the tree, replacing it with folio_mapped()
- "mm/damon: let DAMON be paused and resumed" (SeongJae Park)
Allow DAMON to be paused and resumed without losing its current state
- "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad
Usama Anjum)
Simplify and speed up kasan by removing its ineffective tagging of
stacks and page tables
- "mm/damon/reclaim,lru_sort: monitor all system rams by default"
(SeongJae Park)
Simplify deployment on diverse hardware like NUMA systems by updating
DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the
physical address range covering all System RAM areas by default,
replacing the overly restrictive behavior that only targeted the
single largest memory block to save on negligible overhead
- "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae
Park)
Update some DAMON docs
- "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin)
Switch zone->lock handling over to using the guard() mechanisms
- "mm/filemap: tighten mmap_miss hit accounting" (fujunjie)
Fix a flaw where the mmap_miss counter over-credited page cache hits
during fault-arounds and page-fault retries. This results in
significant reduction of redundant synchronous mmap readahead I/O,
drastically cutting down execution time and gigabytes read for sparse
random or strided memory access workloads
- "selftests/cgroup: Fix false positive failures in test_percpu_basic"
(Li Wang)
Fix a couple of false-positives in the cgroup kmem selftests
- "mm/damon/reclaim: support monitoring intervals auto-tuning"
(SeongJae Park)
Add a new parameter to DAMON permitting DAMON_RECLAIM to
automatically tune DAMON's sampling and aggregation intervals
- "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park)
Change DAMON_STAT to provide the pid of its kdamond
- "mm/kmemleak: dedupe verbose scan output" (Breno Leitao)
Remove large amounts of duplicated backtraces from the verbose-mode
kmemleak output
- "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David
Hildenbrand)
Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to
removing it entirely in a later series
- "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan)
Prevent users from passing a non-power-of-2 value of `addr_unit', as
this later results in undesirable behavior
- "mm: document read_pages and simplify usage" (Frederick Mayle)
- "tools/mm/page-types: Fix misc bugs" (Ye Liu)
Fix three issues in tools/mm/page-types.c
- "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman)
Implement several cleanups in the page allocator and related code
- "mm, swap: swap table phase IV: unify allocation" (Kairui Song)
Unify the allocation and charging of anon and shmem swap in folios,
provides better synchronization, consolidates the metadata
management, hence dropping the static array and map, and improves
performance
- "mm/damon: introduce data attributes monitoring" (SeongJae Park(
Extend DAMON to monitor general data attributes other than accesses
- "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra)
Implement the TODO in vrealloc() to unmap and free unused pages when
shrinking across a page boundary
- "mm/damon: documentation and comment fixes" (niecheng)
- "remove mmap_action success, error hooks" (Lorenzo Stoakes)
Eliminate custom hooks from mmap_action by removing the problematic
success_hook which allowed drivers to improperly access uninitialized
VMAs. It replaces the error_hook with a simple error-code field and
updates the memory char driver accordingly
- "mm/damon: minor improvements for code readability and tests"
(SeongJae Park)
- "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym
Shcherba)
- "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike
Rapoport)
- "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and
others)
Clean up and slightly improves MGLRU's reclaim loop and dirty
writeback handling. Large performance improvements are measured
- "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren
Baghdasaryan)
Use per-vma locks when reading /proc/pid/smaps and numa_maps similar
to reduce contention on central mmap_lock
- "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()"
(Ran Xiaokai)
Some cleanup work in the THP code
- "selftests/memfd: fix compilation warnings" (Konstantin Khorenko)
Fix a few build glitches in the memfd selftest code.
- "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel
Butt)
Resolve a 68% performance regression caused by NUMA-node cache
thrashing around struct obj_stock_pcp by shrinking its existing
fields and expanding it into a multi-slot array that caches up to
five obj_cgroup pointers per CPU, allowing per-node variants of the
same memcg to coexist within a single 64-byte cache line.
- "zram: writeback fixes" (Sergey Senozhatsky)
address a couple of unrelated zram writeback issues
- "mm: switch THP shrinker to list_lru" (Johannes Weiner)
Resolve NUMA-awareness issues and streamlines callsite interaction by
refactoring and extending the list_lru API to completely replace the
complex, open-coded deferred split queue for Transparent Huge Pages
- "mm: improve large folio readahead for exec memory" (Usama Arif)
Improve large-folio readahead on systems like 64K-page arm64 by
preventing the mmap_miss check from permanently disabling
target-oriented VM_EXEC readahead, and by generalizing the
force_thp_readahead gate to support mappings with any usefully large
maximum folio order under the cache cap.
- "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau)
Fix a bunch of minor issues in the userfaultfd/pagemap, all of which
were flagged by Sashiko review of proposed new material
- "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
vmemmap_check_pmd()" (Muchun Song)
Provide generic versions of these two functions so the four
arch-specific implementations can be removed.
- "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap
device" (Youngjun Park)
Address a uswsusp-vs-swapoff race and reduces the swap device
reference taking/releasing frequency.
- "mm/hmm: A fix and a selftest" (Dev Jain)
* tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries
fs/proc/task_mmu: do not warn on seeing non-migration pmd entry
lib/test_hmm: check alloc_page_vma() return value and handle OOM
mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX
mm/swap: remove redundant swap device reference in alloc/free
mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device
mm/filemap: use folio_next_index() for start
vmalloc: fix NULL pointer dereference in is_vm_area_hugepages()
sparc/mm: drop vmemmap_check_pmd helper and use generic code
loongarch/mm: drop vmemmap_check_pmd helper and use generic code
riscv/mm: drop vmemmap_pmd helpers and use generic code
arm64/mm: drop vmemmap_pmd helpers and use generic code
mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
rust: page: mark Page::nid as inline
userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks
userfaultfd: gate must_wait writability check on pte_present()
mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade
fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry()
fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
...
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Pull bitmap updates from Yury Norov:
"This includes the new FIELD_GET_SIGNED() helper,
bitmap_print_to_pagebuf() removal, RISCV/bitrev support, and a couple
cleanups.
- new handy helper FIELD_GET_SIGNED() (Yury)
- arch test_and_set_bit_lock() and clear_bit_unlock() cleanup (Randy)
- __bf_shf() simplification (Yury)
- bitmap_print_to_pagebuf() removal (Yury)
- RISCV/bitrev conditional support (Jindie, Yury)"
* tag 'bitmap-for-7.2' of https://github.com/norov/linux:
MAINTAINERS: BITOPS: include bitrev.[ch]
arch/riscv: Add bitrev.h file to support rev8 and brev8
bitops: Define generic___bitrev8/16/32 for reuse
lib/bitrev: Introduce GENERIC_BITREVERSE
arch: select HAVE_ARCH_BITREVERSE conditionally on BITREVERSE
bitmap: fix find helper documentation
bitmap: drop bitmap_print_to_pagebuf()
cpumask: switch cpumap_print_to_pagebuf() to using scnprintf()
bitfield: wire __bf_shf to __builtin_ctzll
bitops: use common function parameter names
ptp: switch to using FIELD_GET_SIGNED()
rtc: rv3032: switch to using FIELD_GET_SIGNED()
wifi: rtw89: switch to using FIELD_GET_SIGNED()
iio: mcp9600: switch to using FIELD_GET_SIGNED()
iio: pressure: bmp280: switch to using FIELD_GET_SIGNED()
iio: magnetometer: yas530: switch to using FIELD_GET_SIGNED()
iio: intel_dc_ti_adc: switch to using FIELD_GET_SIGNED()
x86/extable: switch to using FIELD_GET_SIGNED()
bitfield: add FIELD_GET_SIGNED()
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Pull bpf updates from Alexei Starovoitov:
"Major changes:
- Recover from BPF arena page faults using a scratch page and add
ptep_try_set() for lockless empty-slot installs on x86 and arm64.
This allows BPF kfuncs to access arena pointers directly.
The 'arena_direct_access' stable branch was created for this work
and was pulled into sched-ext and bpf-next trees (Tejun Heo, Kumar
Kartikeya Dwivedi)
- Lift old restriction and support 6+ arguments in BPF programs and
kfuncs on x86 and arm64 (Yonghong Song, Puranjay Mohan)
Other features and fixes:
- Add 24-bit BTF vlen and reclaim unused bits in the BTF UAPI to ease
addition of new BTF kinds (Alan Maguire)
- Raise the maximum BPF call chain depth from 8 to 16 frames (Alexei
Starovoitov)
- Refactor object relationship tracking in the verifier and fix a
dynptr use-after-free bug (Amery Hung)
- Harden the signed program loader and reject exclusive maps as inner
maps (Daniel Borkmann)
- Replace the verifier min/max bounds fields with a circular number
(cnum) representation and improve 32->64 bit range refinements
(Eduard Zingerman)
- Introduce the arena library and runtime (libarena) with a buddy
allocator, rbtree and SPMC queue data structures, ASAN support and
a parallel test harness. Allow subprograms to return arena pointers
and switch to a BTF type-tag based __arena annotation (Emil
Tsalapatis)
- Cache build IDs in the sleepable stackmap path and avoid faultable
build ID reads under mm locks (Ihor Solodrai)
- Introduce the tracing_multi link to attach a single BPF program to
many kernel functions at once. Allow specifying the uprobe_multi
target via FD (Jiri Olsa)
- Extend the bpf_list family of kfuncs with bpf_list_add/del(), and
bpf_list_is_first/is_last/empty() (Kaitao Cheng)
- Extend the BPF syscall with common attributes support for
prog_load, btf_load and map_create (Leon Hwang)
- Wrap rhashtable as BPF map (Mykyta Yatsenko, Herbert Xu)
- Add sleepable support for tracepoint programs and fix deadlocks in
LRU map due to NMI reentry (Mykyta Yatsenko)
- Fix OOB access in bpf_flow_keys, fix nullness analysis of inner
arrays, enforce write checks for global subprograms (Nuoqi Gui)
- Report the maximum combined stack depth and print a breakdown of
instructions processed per subprogram (Paul Chaignon)
- Add an XDP load-balancer benchmark and arm64 JIT support for stack
arguments (Puranjay Mohan)
- Add kfuncs to traverse over wakeup_sources (Samuel Wu)
- Allow sleepable BPF programs to use LPM trie maps directly (Vlad
Poenaru)
- Many more fixes and cleanups across the verifier, BTF, sockmap,
devmap, bpffs, security hooks, s390/riscv/loongarch JITs,
rqspinlock, libbpf, bpftool, selftests"
* tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (336 commits)
selftests/bpf: Work around llvm stack overflow in crypto progs
selftests/bpf: add test for bpf_msg_pop_data() overflow
bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check
sockmap: Fix use-after-free in udp_bpf_recvmsg()
bpf, sockmap: keep sk_msg copy state in sync
bpf, sockmap: Fix wrong rsge offset in bpf_msg_push_data()
bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
selftsets/bpf: Retry map update on helper_fill_hashmap()
selftests/bpf: Add test for sleepable lsm_cgroup rejection
selftests/bpf: Add test to verify the fix for bpf_setsockopt() helper
bpf: Fix bpf_get/setsockopt to tos for ipv4-mapped ipv6 socket
selftests/bpf: Avoid static LLVM linking for cross builds
selftests/bpf: Use common CFLAGS for urandom_read
selftests/bpf: Initialize operation name before use
tools/bpf: build: Append extra cflags
libbpf: Initialize CFLAGS before including Makefile.include
bpftool: Append extra host flags
bpftool: Avoid adding EXTRA_CFLAGS to HOST_CFLAGS
bpftool: Pass host flags to bootstrap libbpf
selftests/bpf: correct CONFIG_PPC64 macro name in comment
...
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Pull x86 mm updates from Dave Hansen:
"There's a small comment fixup, followed by an actual bug fix. The bug
fix is slightly new territory for us. It fixes a real regression, but
it is from ~6.18 not a _new_ regression. It was mostly only biting
folks doing hotplug memory testing. So, it was queued in here and held
for the merge window instead of going via x86/urgent.
- Fix freeing of PMD-sized vmemmap pages
- Update comment about pgd_list"
* tag 'x86_mm_for_7.2-rc1' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/mm: Fix freeing of PMD-sized vmemmap pages
x86: Update comment about pgd_list
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Pull x86 cleanups from Borislav Petkov:
- The usual pile of cleanups and fixlets the cat dragged in
* tag 'x86_cleanups_for_v7.2_rc1' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Remove obsolete aperfmperf_get_khz() declaration
x86/pmem: Check for platform_device_alloc() retval
x86/platform/uv: Use str_enabled_disabled() in uv_nmi_setup_hubless_intr()
x86/cpu: Keep the PROCESSOR_SELECT menu together
x86/tlb: Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
x86/purgatory: Fix #endif comment
x86/boot: Get rid of kstrtoull()
x86/boot/compressed: Use boot_kstrtoul() for hugepages= parsing
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Pull x86 cpuid updates from Ingo Molnar:
- CPUID API updates (Ahmed S. Darwish):
- Introduce a centralized CPUID parser
- Introduce a centralized CPUID data model
- Introduce <asm/cpuid/leaf_types.h>
- Rename cpuid_leaf()/cpuid_subleaf() APIs
- treewide: Explicitly include the x86 CPUID headers
- Update to x86-cpuid-db v3.1 (Maciej Wieczor-Retman)
- Continued removal of pre-i586 support and related simplifications
(Ingo Molnar)
- Add Intel CPU model number for rugged Panther Lake (Tony Luck)
- Misc fixes, updates and cleanups by Arnd Bergmann, Chao Gao, Lukas
Bulwahn, Sohil Mehta, Maciej Wieczor-Retman.
* tag 'x86-cpu-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (25 commits)
x86/cpu: Make CONFIG_X86_CX8 unconditional
x86/cpu: Remove unused !CONFIG_X86_TSC code
x86/cpuid: Update bitfields to x86-cpuid-db v3.1
tools/x86/kcpuid: Update bitfields to x86-cpuid-db v3.1
x86/cpu: Make CONFIG_X86_TSC unconditional
MAINTAINERS: Drop obsolete FPU EMULATOR section
x86/cpu: Fix a F00F bug warning and clean up surrounding code
x86/cpu: Add Intel CPU model number for rugged Panther Lake
x86/cpuid: Introduce a centralized CPUID parser
x86/cpu: Introduce a centralized CPUID data model
x86/cpuid: Introduce <asm/cpuid/leaf_types.h>
x86/cpuid: Rename cpuid_leaf()/cpuid_subleaf() APIs
x86/cpu: Do not include the CPUID API header in asm/processor.h
Documentation: core-api/cpu_hotplug: Remove stale cpu0_hotplug docs
x86/cpu, cpufreq: Remove AMD ELAN support
x86/fpu: Remove the math-emu/ FPU emulation library
x86/fpu: Remove the 'no387' boot option
x86/fpu: Remove MATH_EMULATION and related glue code
treewide: Explicitly include the x86 CPUID headers
x86/cpu: Remove the CONFIG_X86_INVD_BUG quirk
...
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Pull interrupt core updates from Thomas Gleixner:
- Rework of /proc/interrupt handling:
/proc/interrupts was subject to micro optimizations for a long time,
but most of the low hanging fruit was left on the table. This rework
addresses the major time consuming issues:
- Printing a long series of zeros one by one via a format string
instead of counting subsequent zeros and emitting a string
constant.
- Simplify and cache the conditions whether interrupts should be
printed
- Use a proper iteration over the interrupt descriptor xarray
instead of walking and testing one by one.
- Provide helper functions for the architecture code to emit the
architecture specific counters
- Convert the counter structure in x86 to an array, which
simplifies the output and add mechanisms to suppress unused
architecture interrupts, which just occupy space for nothing.
Adopt the new core mechanisms.
This adjusts the gdb scripts related to interrupt counter statistics
to work with the new mechanisms.
- Prevent a string overflow in the /proc/irq/$N/ directory name
creation code.
* tag 'irq-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/irq: Add missing 's' back to thermal event printout
genirq/proc: Speed up /proc/interrupts iteration
genirq/proc: Runtime size the chip name
genirq: Expose irq_find_desc_at_or_after() in core code
genirq: Add rcuref count to struct irq_desc
genirq/proc: Increase default interrupt number precision to four
genirq: Calculate precision only when required
genirq: Cache the condition for /proc/interrupts exposure
genirq/manage: Make NMI cleanup RT safe
genirq: Expose nr_irqs in core code
scripts/gdb: Update x86 interrupts to the array based storage
x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats
x86/irq: Suppress unlikely interrupt stats by default
x86/irq: Make irqstats array based
genirq/proc: Utilize irq_desc::tot_count to avoid evaluation
genirq/proc: Avoid formatting zero counts in /proc/interrupts
x86/irq: Optimize interrupts decimals printing
genirq/proc: Size interrupt directory names for 10-digit interrupt numbers
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Currently, the memory hot-remove call chain -- arch_remove_memory(),
__remove_pages(), sparse_remove_section() and section_deactivate() -- does
not carry the struct dev_pagemap pointer. This prevents the lower levels
from knowing whether the section was originally populated with vmemmap
optimizations (e.g., DAX with vmemmap optimization enabled).
Without this information, we cannot call vmemmap_can_optimize() to
determine if the vmemmap pages were optimized. As a result, the vmemmap
page accounting during teardown will mistakenly assume a non-optimized
allocation, leading to incorrect memmap statistics.
To lay the groundwork for fixing the vmemmap page accounting, we need to
pass the @pgmap pointer down to the deactivation location. Plumb the
@pgmap argument through the APIs of arch_remove_memory(), __remove_pages()
and sparse_remove_section(), mirroring the corresponding *_activate()
paths.
Link: https://lore.kernel.org/20260428081855.1249045-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <liam@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from
freeing non-boot page tables through __free_pages() to
pagetable_free().
However, the function is also called to free vmemmap pages.
Given that vmemmap pages are not page tables, already the page_ptdesc(page)
is wrong. But worse, pagetable_free() calls:
__free_pages(page, compound_order(page));
Since vmemmap pages are not compound pages (see vmemmap_alloc_block())
-- except for HVO, which doesn't apply here -- only first page of a
PMD-sized vmemmap page is freed, leaking the other ones.
Fix it by properly decoupling pagetable and vmemmap freeing.
free_pagetable() no longer has to mess with SECTION_INFO, as only the
vmemmap is marked like that in register_page_bootmem_memmap().
The indentation in remove_pmd_table() is messed up. Fix that while
touching it.
Bootmem info handling will soon be fixed up. For now, handle it
similar to free_pagetable(), just avoiding the ifdef.
[ dhansen: changelog munging. More imperative voice ]
Fixes: bf9e4e30f353 ("x86/mm: use pagetable_free()")
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Lance Yang <lance.yang@linux.dev>
Link: https://lore.kernel.org/20260429-vmemmap-v2-1-8dfcacffd877@kernel.org
Link: https://patch.msgid.link/20260429-vmemmap-v2-1-8dfcacffd877@kernel.org
Cc: stable@vger.kernel.org
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Having the x86 specific interrupt statistics as a data structure with
individual members instead of an array is just stupid as it requires
endless copy and paste in arch_show_interrupts() and arch_irq_stat_cpu(),
where the latter does not even take the latest interrupt additions into
account. The resulting #ifdef orgy is just disgusting.
Convert it to an array of counters, which does not make a difference in the
actual interrupt hotpath increment as the array index is constant and
therefore not any different than the member based access.
But in arch_show_interrupts() and arch_irq_stat_cpu() this just turns into
a loop, which reduces the text size by ~2k (~12%):
text data bss dec hex filename
19643 15250 904 35797 8bd5 ../build/arch/x86/kernel/irq.o
17355 15250 904 33509 82e5 ../build/arch/x86/kernel/irq.o
Adding a new vector or software counter only requires to update the table
and everything just works. Using the core provided emit function which
speeds up 0 outputs makes it significantly faster.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.196070643@kernel.org
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Using kstrtouint_from_user() instead of copy_from_user() + kstrtouint() makes
the code simpler and less error-prone.
No functional changes.
[ bp: Align function args on opening brace, while at it. ]
Suggested-by: Yury Norov <ynorov@nvidia.com>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Yury Norov <ynorov@nvidia.com>
Link: https://patch.msgid.link/20260117145615.53455-3-fushuai.wang@linux.dev
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BPF arena usage is becoming more prevalent, but kernel <-> BPF communication
over arena memory is awkward today. Data has to be staged through a trusted
kernel pointer with extra code and copying on the BPF side. While reads
through arena pointers can use a fault-safe helper, writes don't have a good
solution. The in-line alternative would need instruction emulation or asm
fixup labels.
Enable direct kernel-side reads and writes within GUARD_SZ / 2 of any
handed-in arena pointer, without bounds checking. A per-arena scratch page
is installed by the arch fault path into empty arena kernel PTEs - x86 from
page_fault_oops() for not-present faults, arm64 from __do_kernel_fault() for
translation faults, both after the existing exception-table and KFENCE
handling. The faulting instruction retries and the access is also reported
through the program's BPF stream, preserving error reporting.
bpf_prog_find_from_stack() resolves the current BPF program (and its arena)
from the kernel stack - no new bpf_run_ctx state is added. Recovery covers
the 4 GiB arena plus the upper half-guard (GUARD_SZ / 2). The lower
half-guard is excluded because well-behaved kfuncs only access forward from
arena pointers. The kfunc-author contract - access at most GUARD_SZ / 2 past
a handed-in pointer - is documented in Documentation/bpf/kfuncs.rst.
The install is lock-free via ptep_try_set(). On race-loss the winning
installer's PTE is already valid, so the access retry succeeds. The arena
clear path uses ptep_get_and_clear() so installer and clearer race through
atomic accessors. No flush_tlb_kernel_range() afterwards. Stale "not mapped"
entries just cause one extra re-fault, cheaper than a global IPI on every
install.
Scratch exists only to keep the kernel from oopsing on an in-line arena
access. Its presence at a PTE means the BPF program has already
malfunctioned, and the violation is reported through the program's BPF
stream. The only requirement for behavior on a scratched PTE is that the
kernel doesn't crash. In particular, any user-side access through such a PTE
may segfault. The shared scratch page is freed once during map destruction.
BPF instruction faults continue to use the existing JIT exception-table
path. This patch changes only the kernel-text fault path. No UAPI flag is
added. The new behavior is the default.
v2: Use ptep_get_and_clear() in apply_range_clear_cb(). (David)
v3: Stub bpf_arena_handle_page_fault() for !CONFIG_BPF_SYSCALL. (lkp)
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Cc: David Hildenbrand <david@kernel.org>
Link: https://lore.kernel.org/r/20260522172219.1423324-3-tj@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The EX_DATA register is laid out such that EX_DATA_IMM occupied MSB.
It's done to make sure that FIELD_GET() will sign-extend the IMM
field during extraction.
To enforce that, all EX_DATA masks are made signed integers. This
works, but relies on the particular implementation of FIELD_GET(),
i.e. masking then shifting, not vice versa; and the particular
placement of the fields in the register.
Switch to using the dedicated FIELD_GET_SIGNED(), and relax those
limitations.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
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This venerable comment got detached from its context when the code moved
in commit 394158559d4c ("x86: move all the pgd_list handling to one
place"). Put it back next to its context. It was originally on
pgd_list_add() but it actually describes pgd_list so put it there.
While moving it, update it to strip away stale and superfluous info.
pageattr.c doesn't exist any more. pgd_list is now required
for all x86 architectures. Also be slightly more precise about what PGDs
are in this list.
[ dhansen: tweak and trim the updated comment a bit ]
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://patch.msgid.link/20260323-pgd_list-comment-v2-1-77ccf2dc77e8@google.com
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Modify all CPUID call sites which implicitly include any of the CPUID
headers to explicitly include them instead.
For KVM's reverse_cpuid.h, just include <asm/cpuid/types.h> since it
references the CPUID_EAX..EDX symbols without using the CPUID APIs.
Note, this allows removing the inclusion of <asm/cpuid/api.h> from within
<asm/processor.h> next. That allows the CPUID API headers to include
<asm/processor.h> without introducing a circular dependency.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20260327021645.555257-1-darwi@linutronix.de
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The kernel's softirq API does not permit re-enabling softirqs while IRQs
are disabled. The reason for this is that local_bh_enable() will not
only re-enable delivery of softirqs over the back of IRQs, it will also
handle any pending softirqs immediately, regardless of whether IRQs are
enabled at that point.
For this reason, commit
d02198550423 ("x86/fpu: Improve crypto performance by making kernel-mode FPU reliably usable in softirqs")
disables softirqs only when IRQs are enabled, as it is not permitted
otherwise, but also unnecessary, given that asynchronous softirq
delivery never happens to begin with while IRQs are disabled.
However, this does mean that entering a kernel mode FPU section with
IRQs enabled and leaving it with IRQs disabled leads to problems, as
identified by Sashiko [0]: the EFI page fault handler is called from
page_fault_oops() with IRQs disabled, and thus ends the kernel mode FPU
section with IRQs disabled as well, regardless of whether IRQs were
enabled when it was started. This may result in schedule() being called
with a non-zero preempt_count, causing a BUG().
So take care to re-enable IRQs when handling any EFI page faults if they
were taken with IRQs enabled.
[0] https://sashiko.dev/#/patchset/20260430074107.27051-1-ivan.hu%40canonical.com
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ivan Hu <ivan.hu@canonical.com>
Cc: x86@kernel.org
Cc: <stable@vger.kernel.org>
Fixes: d02198550423 ("x86/fpu: Improve crypto performance by making kernel-mode FPU reliably usable in softirqs")
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
|
Linus Torvalds
Aneesh Kumar K.V (Arm)
Lorenzo Stoakes (ARM)
Peter Zijlstra
David Hildenbrand (Arm)
Chuyi Zhou
Mike Rapoport (Microsoft)
Denis V. Lunev
Vishal Moola
Borislav Petkov (AMD)
Sang-Heon Jeon
You-Li Lin
Muchun Song
Thomas Gleixner
Fushuai Wang
Kumar Kartikeya Dwivedi
Yury Norov
Brendan Jackman
Ahmed S. Darwish
Ard Biesheuvel