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Zhen Ni
8570b65220 mm/page_owner: add print_mode filter 
Patch series "mm/page_owner: add per-fd filter infrastructure for
print_mode and NUMA filtering", v12.

This patch series introduces per-file-descriptor filtering capabilities to the
page_owner feature.

Problem Statement
=================

In production environments with large memory configurations (e.g.,
250GB+), collecting page_owner information often results in files ranging
from several gigabytes to over 10GB.  This creates significant challenges:

1. Storage pressure on production systems
2. Difficulty transferring large files from production environments
3. Post-processing overhead with tools/mm/page_owner_sort.c

The primary contributor to file size is redundant stack trace information.
While the kernel already deduplicates stacks via stackdepot, page_owner
retrieves and stores full stack traces for each page, only to deduplicate
them again during post-processing.

Additionally, in NUMA-aware environments (e.g., DPDK-based cloud
deployments where QEMU processes are bound to specific NUMA nodes), OOM
events are often node-specific rather than system-wide.  Previously,
page_owner could not filter by NUMA node, forcing users to collect and
analyze data for all nodes.

Solution
========

This patch series introduces a per-file-descriptor filter infrastructure
with two initial filters:

1. **Print Mode Filter**: Outputs only stack handles instead of
   full stack traces. The handle-to-stack mapping can be retrieved
   from the existing show_stacks_handles interface. This dramatically
   reduces output size while preserving all allocation metadata.

2. **NUMA Node Filter**: Allows filtering pages by specific NUMA node(s)
   using flexible nodelist format, enabling targeted analysis of memory
   issues in NUMA-aware deployments.

The per-fd design allows multiple concurrent page_owner reads with
different filters, solving coordination issues in multi-user production
environments.

Implementation
==============

The series is structured as follows:

- Patch 1: Implement print_mode filter infrastructure
  * Add file->private_data to store per-fd filter state
  * Add .open, .release, and .write file operations
  * Support "stack", "handle", and "stack_handle" modes via "mode=" write commands
- Patch 2: Implement NUMA node filter infrastructure
  * Add nid_filter field to per-fd state
  * Support flexible nodelist format via "nid=" write commands (single, multiple, ranges)
  * Validate nodes and reject non-existent nodes using nodes_subset()
- Patch 3: Add page_owner_filter userspace tool
  * Manages per-fd filters via write() interface
  * Provides user-friendly command-line interface
  * Includes comprehensive input validation
- Patch 4: Document filter features and usage

Usage Example
=============

Using the page_owner_filter tool with per-fd filters:

    # ./page_owner_filter -m stack_handle -n "0,2-3" -o page_owner.txt

The tool opens /sys/kernel/debug/page_owner, sets filters via write(),
then reads the filtered output to the specified file (or stdout).

Sample print_mode output (showing handles only):

    Page allocated via order 0, mask 0x0(), pid 0, tgid 0 (swapper),
    ts 0 ns PFN 0x40000 type Unmovable Block 512 type Unmovable
    Flags 0x3fffe0000000000(node=0|zone=0|lastcpupid=0x1ffff)
    handle: 1048577

    Page allocated via order 0, mask 0x252000(__GFP_NOWARN|
    __GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 0, tgid 0 (swapper),
    ts 0 ns PFN 0x40002 type Unmovable Block 512 type Unmovable
    Flags 0x23fffe0000000200(workingset|node=0|zone=0|lastcpupid=0x1ffff)
    handle: 1048577


This patch (of 4):

Add a print_mode filter to page_owner that allows users to choose between
printing stack traces, stack handles, or both, providing flexibility for
different debugging and analysis scenarios.

The filter provides three modes via page_owner:
- Writing "mode=stack" prints stack traces for each page (default)
- Writing "mode=handle" prints only the handle number
- Writing "mode=stack_handle" prints both stack traces and handles

The default stack mode maintains backward compatibility with existing
usage, displaying complete stack traces for each page allocation.

The handle mode dramatically reduces log size and improves performance by
showing only the handle number instead of the full stack trace.  Testing
shows handle mode reduces output size by ~66% (84MB vs 244MB) and improves
read performance by ~4.4x compared to full stack output.  The mapping from
handles to actual stack traces can be obtained via the show_stacks_handles
interface.

The stack_handle mode prints both stack traces and handles, making it
easier to identify pages with the same allocation pattern by comparing
handle numbers instead of comparing large stack traces.

Example usage:
  # Using the page_owner_filter tool (recommended)
  ./page_owner_filter -m stack          # Print only stack traces (default)
  ./page_owner_filter -m handle         # Print only handles
  ./page_owner_filter -m stack_handle   # Print both stack and handles

Sample output (handle mode):
  Page allocated via order 0, migratetype Unmovable, gfp_mask 0x1100ca,
  pid 1, tgid 1 (systemd), ts 123456789 ns
  PFN 0x1000 type Unmovable Block 1 type Unmovable
  Flags 0x3fffe800000084(referenced|lru|active|private|node=0|zone=1)
  handle: 17432583
  ...

This implementation uses per-file-descriptor filter state stored in
file->private_data, allowing each opener to have independent filter
configuration.

Link: https://lore.kernel.org/20260707115411.1714314-1-zhen.ni@easystack.cn
Link: https://lore.kernel.org/20260707115411.1714314-2-zhen.ni@easystack.cn
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Tested-by: Zi Yan <ziy@nvidia.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:54 -07:00
Shivank Garg
3dd5a633a0 mm/migrate: use migrate_info field instead of private 
Add an unsigned long migrate_info member to the struct folio union and use
it to store migration state (anon_vma pointer and FOLIO_WAS_* markers)
instead of using folio->private.  While at it, switch to bitwise OR.

No functional change.

[rdunlap@infradead.org: add missing kernel-doc for @migrate_info]
  Link: https://lore.kernel.org/20260717022146.1290242-1-rdunlap@infradead.org
Link: https://lore.kernel.org/20260701-migrate-cleanups-prep-v2-3-d9e8f17130b1@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:53 -07:00
Shivank Garg
8d76257715 mm/migrate: fix stale list name in migrate_folios_move() comment 
The return-value description in migrate_folios_move() still refers to
unmap_folios, but that list no longer exists.  Update this name to
src_folios.

Link: https://lore.kernel.org/20260701-migrate-cleanups-prep-v2-2-d9e8f17130b1@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:53 -07:00
Shivank Garg
9aaf5aa244 mm/migrate: rename page to folio leftovers 
Patch series "mm/migrate: preparatory cleanups for batch copy and
offload", v2.

This is a small set of mm/migrate cleanups split out of the batch-copy and
offload RFC [1], so they can be reviewed and merged independently ahead of
that larger series.

No functional change intended.


This patch (of 3):

Rename migrate_folio_undo_src()'s page_was_mapped parameter to was_mapped,
unmap_and_move_huge_page() to unmap_and_move_hugetlb_folio(), its
page_was_mapped variable to was_mapped and fix stale "page" wording in its
comments.

Also fix migrate_folio() kerneldoc to say "folio" instead of "page".

Link: https://lore.kernel.org/20260701-migrate-cleanups-prep-v2-0-d9e8f17130b1@amd.com
Link: https://lore.kernel.org/20260701-migrate-cleanups-prep-v2-1-d9e8f17130b1@amd.com
Link: https://lore.kernel.org/all/20260428155043.39251-2-shivankg@amd.com [1]
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: Dev Jain <dev.jain@arm.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:53 -07:00
Kefeng Wang
9bde2240ec mm: migrate_device: use walk_page_range_vma() in migrate_vma_collect() 
migrate_vma_collect() uses walk_page_range() to walk the page table. 
Fortunately, migrate_vma_setup() already validates that the entire range
falls within a single VMA.

Since there is no .test_walk in migrate_vma_walk_ops and VM_PFNMAP was
filtered by migrate_vma_setup(), it's safe to replace walk_page_range()
with walk_page_range_vma() to eliminate an unnecessary find_vma() lookup.

Link: https://lore.kernel.org/20260618092845.3905740-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:53 -07:00
Kefeng Wang
d4c63a378b mm: mlock: use walk_page_range_vma() in mlock_vma_pages_range() 
The mlock_vma_pages_range() uses walk_page_range() to walk the page table.
Fortunately, the caller always passes start/end that falls within a
single VMA, apply_vma_lock_flags() iterates per-VMA, and
apply_mlockall_flags() passes the whole VMA.

Since there is no .test_walk in mlock_walk_ops and VM_PFNMAP was filtered
by vma_supports_mlock(), it's safe to replace walk_page_range() with
walk_page_range_vma() to eliminate an unnecessary find_vma() lookup.

Link: https://lore.kernel.org/20260618092845.3905740-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:52 -07:00
Kefeng Wang
334509572d mm: mprotect: use walk_page_range_vma() in mprotect_fixup() 
In mprotect_fixup(), the PROT_NONE PFN permission check uses
walk_page_range() to walk the page table.  Fortunately, the caller always
passes start/end that falls within a single VMA, the do_mprotect_pkey()
iterates per-VMA via for_each_vma_range(), and setup_arg_pages() passes
the whole VMA.

Note, walk_page_test() isn't called in walk_page_range_vma(), however,
prot_none_test() in prot_none_walk_ops always return 0, so it's safe to
replace walk_page_range() with walk_page_range_vma() to eliminate an
unnecessary find_vma() lookup, also remove unneeded prot_none_test() too.

Link: https://lore.kernel.org/20260618092845.3905740-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:52 -07:00
Kefeng Wang
8fb1ad47dc mm: mincore: use walk_page_range_vma() in do_mincore() 
Patch series "mm: convert to walk_page_range_vma() to eliminate
find_vma()", v2.

walk_page_range() performs a find_vma() lookup on each page table walk. 
For callers that already hold a valid VMA and operate on a known
single-VMA range, this lookup is redundant.  Replace walk_page_range()
with walk_page_range_vma() where the caller guarantees single-VMA
semantics.


This patch (of 4):

do_mincore() uses walk_page_range() to walk the page table.  Fortunately,
the caller always passes start/end that falls within a single VMA, so it's
safe to use the walk_page_range_vma() in do_mincore() to eliminate an
unnecessary find_vma() lookup.

Unlike walk_page_range(), walk_page_range_vma() does not call
walk_page_test(), which handles VM_PFNMAP by invoking ->pte_hole() to skip
the page table walk.  Without this check, PFNMAP PTEs would be treated as
present by mincore_pte_range(), changing the returned residency status. 
Handle VM_PFNMAP explicitly in do_mincore() to preserve the original
behavior.

[akpm@linux-foundation.org: simplify comment, per Pedro]
  Link: https://lore.kernel.org/ajP9bQhmvR9OX0VE@pedro-suse
Link: https://lore.kernel.org/20260618092845.3905740-1-wangkefeng.wang@huawei.com
Link: https://lore.kernel.org/20260618092845.3905740-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:52 -07:00
Ye Liu
90f095b816 mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() 
print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the
start to guard against tail pages and NULL data.  However, it later
re-reads page->memcg_data locklessly in two places:

1: page_memcg_check(page)

2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes
   VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)

If the page is concurrently freed and reallocated as a THP tail page or
slab page between these calls, the VM_BUG_ON assertions can trigger on
CONFIG_DEBUG_VM=y builds, crashing the kernel.

Fix both TOCTOU issues by using the memcg_data snapshot throughout.

Link: https://lore.kernel.org/20260714015117.78351-10-ye.liu@linux.dev
Fixes: fcf8935832 ("mm/page_owner: print memcg information")
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:52 -07:00
Ye Liu
4fd1c85cc0 mm/page_owner: clamp skip_buddy_pages() PFN advance at MAX_ORDER_NR_PAGES boundary 
The lockless buddy_order_unsafe() read can return a garbage order value if
the page is concurrently allocated between the PageBuddy check and the
private read.  If this bogus order is <= MAX_PAGE_ORDER,
skip_buddy_pages() would arbitrarily advance the PFN, potentially jumping
past a MAX_ORDER_NR_PAGES boundary whose pfn_valid() check would have
caught an offline memory section.

In read_page_owner(), which relies solely on boundary-aligned pfn_valid()
to guard pfn_to_page(), skipping the boundary could cause pfn_to_page() to
access an unmapped mem_section.

Clamp the advance so it never crosses the next MAX_ORDER_NR_PAGES
boundary.  This is safe for all three callers: the pageblock-iterating
ones already handle boundary transitions in their outer loops, and for
read_page_owner() the worst case is one extra PageBuddy check per 1024
pages when a bogus order would otherwise push past the boundary.

Link: https://lore.kernel.org/20260714015117.78351-9-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:51 -07:00
Ye Liu
f0bb69130e mm/page_owner: drop redundant page_owner prefix from static symbols 
All of these symbols are file-scoped (static) in page_owner.c, so the
page_owner_ prefix is pure noise.  Rename them to shorter, still-clear
names:

  page_owner_stack_op      -> stack_op
  page_owner_stack_open    -> stack_open
  page_owner_stack_fops    -> stack_fops
  page_owner_pages_threshold -> pages_threshold
  page_owner_threshold_get -> threshold_get
  page_owner_threshold_set -> threshold_set
  page_owner_threshold_fops -> threshold_fops

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-8-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:51 -07:00
Ye Liu
1f5af031ff mm/page_owner: move free_ts_nsec output to free section in __dump_page_owner() 
The free_ts_nsec field is a free-event timestamp, but it was printed in
the allocation summary line alongside ts_nsec (allocation time).  Move it
to the free section where it logically belongs, together with free_pid and
free_tgid.  This also makes __dump_page_owner() consistent with
print_page_owner(), which only prints ts_nsec in the allocation summary.

The output now groups all free-related information (pid, tgid, timestamp,
stack trace) in one place.

No functional change except output formatting.

Link: https://lore.kernel.org/20260714015117.78351-7-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:51 -07:00
Ye Liu
c1c94cf658 mm/page_owner: add missing newline to count_threshold format string 
The DEFINE_SIMPLE_ATTRIBUTE format string for page_owner_threshold_fops is
missing a trailing \n.  simple_attr_read() uses scnprintf() with the
format string, which does not append a newline, so reading
/sys/kernel/debug/page_owner_stacks/count_threshold produces output
without a terminating newline.  Add the missing \n to match the standard
debugfs attribute convention.

Link: https://lore.kernel.org/20260714015117.78351-6-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:51 -07:00
Ye Liu
e90ed51908 mm/page_owner: hoist CONFIG_MEMCG to function level for print_page_owner_memcg() 
The print_page_owner_memcg() function has CONFIG_MEMCG guarding its entire
body via #ifdef inside the function, which leaves a no-op { return ret; }
when the config is disabled.  Hoist the #ifdef to the top level so the
real implementation and the empty stub are two clearly separated
definitions.

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-5-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:50 -07:00
Ye Liu
c95dc0a84b mm: use enum migrate_reason instead of int for migration reason parameters 
Replace all 'int reason' function parameters that carry migrate_reason
values with the proper 'enum migrate_reason' type.  This makes the intent
explicit and leverages compiler type checking.  The affected subsystems
are:

  - page_owner: __folio_set_owner_migrate_reason(),
                folio_set_owner_migrate_reason()
  - migrate: migrate_pages(), migrate_pages_sync(),
             migrate_pages_batch(), migrate_folios_move(),
             migrate_hugetlbs(), unmap_and_move_huge_page()
  - hugetlb: move_hugetlb_state(), htlb_allow_alloc_fallback()
  - trace: mm_migrate_pages and mm_migrate_pages_start events

The 'short last_migrate_reason' struct field and internal helper parameter
in page_owner are intentionally left as 'short' since they store per-page
metadata where size matters.

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-4-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:50 -07:00
Ye Liu
7eeed888c9 mm/page_owner: add MR_NEVER to enum migrate_reason and use it for last_migrate_reason 
The last_migrate_reason field uses -1 as a sentinel value to mean "no
migration has happened".  Replace the four bare -1 occurrences by adding a
proper MR_NEVER member to enum migrate_reason, defining a corresponding
"never_migrated" string in the MIGRATE_REASON trace macro, and updating
the GDB page_owner script to use MR_NEVER instead of the hardcoded -1 so
that lx-dump-page-owner does not incorrectly report unmigrated pages as
migrated.

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-3-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:50 -07:00
Ye Liu
53472eb262 mm/page_owner: extract skip_buddy_pages() helper to unify buddy page skipping 
Patch series "mm/page_owner: misc cleanups", v6.

This series collects a few cleanups for mm/page_owner.c that have been
accumulated while reading through the file.  There is no functional change
-- the goal is to make the code easier to read and maintain.

Patch 1 consolidates three identical PageBuddy skip blocks into a single
skip_buddy_pages() helper, eliminating the duplication and keeping the
lockless-read comment in one place.

Patch 2 replaces the -1 magic number used for "never migrated" with a
proper MR_NEVER member in enum migrate_reason, adds the corresponding
"never_migrated" string in the MIGRATE_REASON trace macro, and updates the
GDB page_owner script to use MR_NEVER so that lx-dump-page-owner correctly
detects unmigrated pages.

Patch 3 follows up by converting the remaining 'int reason' parameters
throughout the migration and hugetlb callchains to 'enum migrate_reason',
making the type explicit and gaining compiler checking.  The 'short
last_migrate_reason' struct field in page_owner is intentionally left as
'short' since it is per-page metadata where size matters.

Patch 4 hoists the CONFIG_MEMCG guard out of print_page_owner_memcg()'s
body so that the real implementation and the empty stub are two clearly
separate definitions, the common kernel idiom.

Patch 5 adds a missing \n to the count_threshold debugfs attribute format
string so that cat(1) output is properly terminated.

Patch 6 moves free_ts_nsec from the allocation summary line to the free
section in __dump_page_owner(), grouping it with free_pid and free_tgid
where it logically belongs.  This also makes the dump output consistent
with print_page_owner().

Patch 7 drops the redundant page_owner_ prefix from file-scoped static
symbols (stack_fops, threshold_fops, etc.).  Since they cannot collide
across translation units, the prefix carries no information.

Patch 8 clamps the PFN advance in skip_buddy_pages() at the next
MAX_ORDER_NR_PAGES boundary.  The lockless buddy_order_unsafe() read can
return a garbage order value if the page is concurrently allocated between
the PageBuddy check and the private read, potentially causing the PFN to
advance past the next bounadry whose pfn_valid() check would have caught
an offline memory section.  In read_page_owner(), which relies solely on
boundary-aligned pfn_valid() to guard pfn_to_page(), this could lead to an
unmapped mem_section access.

Patch 9 avoids two TOCTOU issues in print_page_owner_memcg() by reusing
the page->memcg_data snapshot already taken via READ_ONCE at the top of
the function throughout, instead of calling page_memcg_check() and
PageMemcgKmem() which re-read page->memcg_data locklessly with VM_BUG_ON
assertions.  If the page is concurrently freed and reallocated as a THP
tail or slab page between the initial guards and these later calls, those
assertions can fire on CONFIG_DEBUG_VM=y builds.  The OBJEXTS (slab) case
is also simplified with an early return since objcg != memcg for slabs.


This patch (of 6):

Three places in page_owner.c duplicate the same pattern: check if a page
is PageBuddy, read its order via buddy_order_unsafe(), advance the pfn
past the buddy block if the order is valid, and continue.

Consolidate them into a single inline helper skip_buddy_pages().  The
function returns true (skip) for any buddy page and advances @pfn past the
block when the order is valid; returns false if the page is not a buddy
page and should be processed normally.

The old init_pages_in_zone() variant used "order > 0" as an extra guard
before advancing pfn, but the continue was unconditional and (1UL << 0) -
1 == 0, so the behaviour is identical.  The comment about zone->lock is
preserved in the helper's kernel-doc.

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-1-ye.liu@linux.dev
Link: https://lore.kernel.org/20260714015117.78351-2-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:49 -07:00
Breno Leitao
cdf95d6b33 mm/kmemleak: stop the per-cpu and struct page scans early too 
The per-cpu and struct page scan loops have no reschedule-stop check of
their own: once a scan is interrupted they keep calling scan_block() for
every remaining block, which scans nothing useful.

Propagate scan_block()'s interrupted status through scan_large_block() and
break both loops as soon as it is set.

Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-3-acecd7d7fd92@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Qian Cai <cai@lca.pw>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:49 -07:00
Breno Leitao
eb11f56eec mm/kmemleak: stop the task stack scan early when interrupted 
scan_block() already checks scan_should_stop() for every pointer and bails
out of the current block, but the task stack walk cannot tell and keeps
issuing a separate scan_should_stop() between every task.

Return that status from scan_block() and use it as the task stack loop
condition, so the walk stops as soon as a scan is interrupted.

Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-2-acecd7d7fd92@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Qian Cai <cai@lca.pw>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:49 -07:00
Breno Leitao
5d10d4e19e mm/kmemleak: avoid soft lockup when scanning task stacks 
Patch series "mm/kmemleak: avoid soft lockup when scanning task", v3.

kmemleak_scan() scans every task stack under one rcu_read_lock() with no
reschedule point, which can trip the soft lockup watchdog on hosts with
very many threads.

That prints the following message, depending on the workload+host
configuration:

      watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]
       scan_block
       kmemleak_scan
       kmemleak_scan_thread
       kthread

Patch 1 walks the tasks with find_ge_pid() so the scan reschedules between
tasks

Patches 2-3 let the scan loops stop early once a scan is interrupted.


This patch (of 3):

kmemleak_scan() walks every thread and scans its kernel stack under a
single rcu_read_lock() with no reschedule point.  On a host with very many
threads -- amplified by KASAN/lockdep in debug builds -- this loop can hog
a CPU long enough to trip the soft lockup watchdog:

  watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]
   scan_block
   kmemleak_scan
   kmemleak_scan_thread
   kthread

A cond_resched() cannot be added directly: the loop runs inside an RCU
read-side critical section.

Walk the tasks one PID at a time with find_ge_pid(), taking the RCU read
lock only to look up and pin each task.  The stack is then scanned with no
lock held, so cond_resched() runs between tasks and the scan stops early
on scan_should_stop().  This follows the next_tgid()/task_seq_get_next()
iteration pattern and keeps each RCU critical section short.

Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-0-acecd7d7fd92@debian.org
Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-1-acecd7d7fd92@debian.org
Fixes: c4b28963fd ("mm/kmemleak: rely on rcu for task stack scanning")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:49 -07:00
Ethan Nelson-Moore
aa38f2454b mm: hugetlb: correct CONFIG_CGROUP_HUGETLB macro name in comment 
A comment in <linux/hugetlb_cgroup.h> incorrectly refers to
CONFIG_MEM_RES_CTLR_HUGETLB, which has never existed in the kernel,
instead of CONFIG_CGROUP_HUGETLB.  Correct it.

Discovered while searching for CONFIG_* symbols referenced in code but not
defined in any Kconfig file.

Link: https://lore.kernel.org/20260616000135.62815-1-enelsonmoore@gmail.com
Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:48 -07:00
Markus Elfring
24e9b62985 mm/vmalloc: use more common error handling code in pcpu_get_vm_areas() 
Use an existing label once more so that a bit of exception handling can be
better reused at the end of this function implementation.

This issue was detected by using the Coccinelle software.

Link: https://lore.kernel.org/453375c4-c3ca-4e6f-8880-0e6ff3c74ee3@web.de
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:48 -07:00
Sang-Heon Jeon
73e28dccd0 arch_numa: remove redundant nodemask clears in numa_init() 
numa_init() clears numa_nodes_parsed, node_possible_map and
node_online_map, then calls numa_memblks_init(), which clears the same
nodemasks.  Nothing uses them in between.

These clears have been redundant since commit 767507654c ("arch_numa:
switch over to numa_memblks") made numa_init() use numa_memblks_init().

No functional change.

Link: https://lore.kernel.org/20260617163919.2544899-1-ekffu200098@gmail.com
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:48 -07:00
Andrew Morton
d623ed9ba0 csky: implement flush_cache_vmap() in C 
To avoid getting an unused-var warning from

	unsigned long start = something;
	...
	flush_cache_vmap(start, ...);

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202606291606.9h8aGniQ-lkp@intel.com/
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Wen Jiang <jiangwen6@xiaomi.com>
Cc: Wen Jiang <jiangwenxiaomi@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xueyuan Chen <xueyuan.chen21@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:48 -07:00
Ben Dooks
cdea9364e4 mm/page_alloc: don't build vm_numa_stat_key if CONFIG_NUMA=n 
vm_numa_stat_key is only exported if CONFIG_NUMA is set, so avoid the
following warning by guarding it in an #ifdef on CONFIG_NUMA:

mm/page_alloc.c:165:1: warning: symbol 'vm_numa_stat_key' was not declared. Should it be static?

Link: https://lore.kernel.org/20260618100614.1321950-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:47 -07:00
Kefeng Wang
a35d8872da mm: remove PageTransCompound() 
Remove the last user of PageTransCompound() in ksm and get rid of
PageTransCompound().

Link: https://lore.kernel.org/20260618113523.3913307-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Xu Xin <xu.xin16@zte.com.cn>
Tested-by: Xu Xin <xu.xin16@zte.com.cn>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:47 -07:00
Kaitao Cheng
8725ae13f0 mm/percpu: avoid IO/FS reclaim in backing allocations 
Commit 9a5b183941 ("mm, percpu: do not consider sleepable allocations
atomic") allows sleepable GFP_NOIO and GFP_NOFS percpu allocations to take
pcpu_alloc_mutex.  This avoids premature allocation failures, but it also
makes the mutex visible to callers from constrained IO/FS contexts.

Thread A calls pcpu_alloc_noprof() with GFP_KERNEL and takes
pcpu_alloc_mutex.  Since the internal allocation is not constrained by
NOFS, it may enter FS reclaim while still holding pcpu_alloc_mutex,
creating a dependency like: pcpu_alloc_mutex -> fs_reclaim -> FS lock

At the same time, Thread B may already hold an FS lock and then call
pcpu_alloc_noprof() with GFP_NOFS.  It will try to acquire
pcpu_alloc_mutex and block, creating the reverse dependency: FS lock ->
pcpu_alloc_mutex

This can still form a potential deadlock cycle.

Avoid the dependency by restricting percpu backing allocations to
GFP_NOIO.  The public allocation still uses the caller's GFP context to
decide whether it may block, but the internal memory allocations performed
while pcpu_alloc_mutex is held cannot recurse into IO or FS reclaim.

Link: https://lore.kernel.org/20260618130414.96383-5-kaitao.cheng@linux.dev
Fixes: 9a5b183941 ("mm, percpu: do not consider sleepable allocations atomic")
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Shivam Kalra <shivamkalra98@zohomail.in>
Cc: Tejun Heo <tj@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:47 -07:00
Kaitao Cheng
17fcdd8699 mm/percpu: make cached pages lookup explicit 
pcpu_depopulate_chunk() only needs the temporary pages array that was
already allocated by an earlier successful population attempt.  Passing
GFP_KERNEL to pcpu_get_pages() in this path is misleading because the
depopulation path is not expected to allocate the array.

Teach pcpu_get_pages() to treat a zero gfp mask as a cached-only lookup
and add pcpu_get_pages_cached() for that use case.  This keeps allocation
on the populate path tied to the caller supplied GFP mask while making the
depopulate path's dependency on the cached array explicit.

Link: https://lore.kernel.org/20260618130414.96383-4-kaitao.cheng@linux.dev
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Suggested-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Shivam Kalra <shivamkalra98@zohomail.in>
Cc: Tejun Heo <tj@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:47 -07:00
Kaitao Cheng
881adc51b2 mm/percpu: honor GFP constraints when populating chunks 
pcpu_alloc_noprof() derives pcpu_gfp from the caller supplied GFP mask and
passes it down to pcpu_populate_chunk().  pcpu_alloc_pages() already uses
that mask for backing page allocation.

However, the populate slow path still has internal allocations and page
table allocations which can lose the caller's allocation context.  The
temporary pages array is allocated by pcpu_get_pages() with GFP_KERNEL,
and pcpu_map_pages() maps the backing pages through
vmap_pages_range_noflush() using GFP_KERNEL.  The latter can allocate
vmalloc page tables implicitly, so a caller which deliberately uses
GFP_NOFS or GFP_NOIO can still enter FS or IO reclaim while populating a
percpu chunk.

This has the same concern as chunk creation: callers such as blk-cgroup
may use GFP_NOIO because they hold locks which can be involved in queue
freeze or IO reclaim dependencies.  If an allocation reaches the percpu
slow path and needs to populate previously unbacked pages, the internal
GFP_KERNEL allocations can defeat that context.

One possible case is blk-cgroup after commit 5d726c4dbe ("blk-cgroup:
fix possible deadlock while configuring policy").  blkg_conf_prep() now
serializes against blkcg_deactivate_policy() with q->blkcg_mutex, and
blkg_alloc() was changed to GFP_NOIO for that reason:

  CPU0: blkg_conf_prep()
    mutex_lock(q->blkcg_mutex)
    blkg_alloc(..., GFP_NOIO)
      alloc_percpu_gfp(..., GFP_NOIO)
        pcpu_alloc_noprof(..., GFP_NOIO)
          pcpu_populate_chunk(GFP_NOIO)
            pcpu_get_pages()
	    pcpu_map_pages()
              -> if the selected percpu chunk has unpopulated pages,
	         chunk population may do internal GFP_KERNEL allocations
              -> direct reclaim / writeback can issue IO to this queue
              -> IO waits because the queue is frozen

  CPU1: blkcg_deactivate_policy()
    blk_mq_freeze_queue(q)
    mutex_lock(q->blkcg_mutex)
      -> waits for CPU0
    ... unfreeze only happens after q->blkcg_mutex is acquired/released

So the concern is that the caller deliberately uses GFP_NOIO because it
may hold a lock which can be acquired after queue freeze, but the percpu
slow path can temporarily lose that allocation context.

Pass pcpu_gfp through pcpu_get_pages(), pcpu_map_pages() and
__pcpu_map_pages().  Apply the corresponding memalloc scope around
vmap_pages_range_noflush(), because vmalloc page table allocation does not
pass the GFP mask down explicitly.  Keep the first chunk setup path using
GFP_KERNEL, matching the previous early-init behavior.

Link: https://lore.kernel.org/20260618130414.96383-3-kaitao.cheng@linux.dev
Fixes: 9a5b183941 ("mm, percpu: do not consider sleepable allocations atomic")
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Acked-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Shivam Kalra <shivamkalra98@zohomail.in>
Cc: Tejun Heo <tj@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:46 -07:00
Kaitao Cheng
dec068de6d mm/vmalloc: honor GFP constraints in pcpu_get_vm_areas() 
Patch series "mm/percpu: Fix possible NOFS/NOIO reclaim recursion", v4.

Commit 9a5b183941 ("mm, percpu: do not consider sleepable allocations
atomic") allowed GFP_NOFS and GFP_NOIO percpu allocations to use
pcpu_alloc_mutex and the chunk creation slow path.  This restored the
allocation capability that was lost when those constrained allocations
were treated as atomic, but it also makes the percpu slow path visible to
callers from constrained reclaim contexts.

There are two related problems.

First, the create and populate slow paths do not fully preserve the
caller's allocation constraints.  pcpu_alloc_noprof() derives pcpu_gfp
from the caller supplied GFP mask and passes it down to the percpu backing
page allocator.  However, chunk creation calls pcpu_get_vm_areas(), and
chunk population can allocate temporary metadata or vmalloc page tables
while mapping backing pages.  Those internal allocations can still use
GFP_KERNEL, so a caller using GFP_NOFS or GFP_NOIO can enter unconstrained
FS or IO reclaim while holding pcpu_alloc_mutex.

One possible case is blk-cgroup after commit 5d726c4dbe ("blk-cgroup:
fix possible deadlock while configuring policy").  blkg_conf_prep() now
serializes against blkcg_deactivate_policy() with q->blkcg_mutex, and
blkg_alloc() uses GFP_NOIO because queue freeze and IO reclaim
dependencies can otherwise deadlock.  If the percpu slow path loses that
GFP_NOIO context, direct reclaim or writeback can issue IO to a frozen
queue while q->blkcg_mutex is held.

Second, allowing sleepable GFP_NOFS/GFP_NOIO allocations to take
pcpu_alloc_mutex means that unconstrained backing allocations made under
the mutex can create an FS/IO reclaim dependency against a constrained
caller which already holds an FS or IO lock and then waits for
pcpu_alloc_mutex.

This series fixes those issues in three steps:

  - pass the caller supplied GFP mask into pcpu_get_vm_areas() and use it
    for vmalloc metadata and KASAN shadow allocations;
  - pass the GFP mask through the chunk population path, including the
    temporary pages array and vmalloc page table allocation scope;
  - restrict percpu backing allocations performed while holding
    pcpu_alloc_mutex to GFP_NOIO, so they cannot recurse into IO or FS
    reclaim.

This keeps sleepable GFP_NOFS/GFP_NOIO percpu allocations working, while
avoiding the reclaim recursion risks introduced by making those
allocations eligible for the mutex-protected slow path.


This patch (of 4):

pcpu_alloc_noprof() derives pcpu_gfp from the caller supplied GFP mask and
passes it down to the backing percpu allocator.  However, when the percpu
vmalloc allocator has to create a new chunk, pcpu_create_chunk() calls
pcpu_get_vm_areas() to allocate the corresponding vmalloc areas.

pcpu_get_vm_areas() currently performs its internal allocations with
GFP_KERNEL, including vmap area metadata, vm_struct metadata and KASAN
vmalloc shadow population.  This means that a caller which deliberately
uses GFP_NOFS or GFP_NOIO can still enter FS or IO reclaim while creating
the vmalloc areas for a new percpu chunk.

One possible case is blk-cgroup after commit 5d726c4dbe ("blk-cgroup:
fix possible deadlock while configuring policy").  blkg_conf_prep() now
serializes against blkcg_deactivate_policy() with q->blkcg_mutex, and
blkg_alloc() was changed to GFP_NOIO for that reason:

  CPU0: blkg_conf_prep()
    mutex_lock(q->blkcg_mutex)
    blkg_alloc(..., GFP_NOIO)
      alloc_percpu_gfp(..., GFP_NOIO)
        pcpu_alloc_noprof(..., GFP_NOIO)
	  pcpu_create_chunk(GFP_NOIO)
	    pcpu_get_vm_areas()
              -> if percpu chunks are exhausted, chunk create may do
                 internal GFP_KERNEL allocations
              -> direct reclaim / writeback can issue IO to this queue
              -> IO waits because the queue is frozen

  CPU1: blkcg_deactivate_policy()
    blk_mq_freeze_queue(q)
    mutex_lock(q->blkcg_mutex)
      -> waits for CPU0
    ... unfreeze only happens after q->blkcg_mutex is acquired/released

So the concern is that the caller deliberately uses GFP_NOIO because it
may hold a lock which can be acquired after queue freeze, but the percpu
slow path can temporarily lose that allocation context.

Pass the caller supplied GFP mask from pcpu_create_chunk() to
pcpu_get_vm_areas(), and use it for the internal vmalloc metadata and
KASAN shadow allocations.

Link: https://lore.kernel.org/20260618130414.96383-1-kaitao.cheng@linux.dev
Link: https://lore.kernel.org/20260618130414.96383-2-kaitao.cheng@linux.dev
Fixes: 9a5b183941 ("mm, percpu: do not consider sleepable allocations atomic")
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Shivam Kalra <shivamkalra98@zohomail.in>
Acked-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:46 -07:00
Thomas Huth
5339ec29f9 mm: replace __ASSEMBLY__ with __ASSEMBLER__ in memory management header files 
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a macro that
only gets defined by the Makefiles in the kernel.  This can be very
confusing when switching between userspace and kernelspace coding, or when
dealing with uapi headers that rather should use __ASSEMBLER__ instead. 
So let's standardize now on the __ASSEMBLER__ macro that is provided by
the compilers.

This is a completely mechanical patch (done with a simple "sed -i"
statement).

Link: https://lore.kernel.org/20260619131830.229804-1-thuth@redhat.com
Signed-off-by: Thomas Huth <thuth@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:46 -07:00
Chi Zhiling
32cd1afeca mm/filemap: reduce unnecessary xarray lookups in filemap_get_folios_contig() 
Apply the same optimization used in filemap_get_read_batch() by moving the
boundary check from the loop condition to before xas_next(), avoiding an
unnecessary xarray lookup and reducing branches in the fast path.

Link: https://lore.kernel.org/20260620062446.351475-3-chizhiling@163.com
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:45 -07:00
Chi Zhiling
e1c345582c mm/filemap: reduce unnecessary xarray lookups when read cached pages 
Patch series "mm/filemap: reduce unnecessary xarray lookups".

This series optimizes xarray lookups in filemap by avoiding redundant
iterations after obtaining the last needed folio.  The boundary check is
moved to before advancing the xarray iterator, eliminating unnecessary
lookups and branches in the fast path.  This reduces the overhead of
filemap_get_read_batch() from 2.91% to 2.53% in 4k read tests.


This patch (of 2):

When reading small amounts of data from the page cache, only a single
folio is typically returned from filemap_read_get_batch().  In this case,
calling xas_advance() or xas_next() after adding the folio to the batch is
unnecessary and only introduces extra branches.

The same issue exists for large reads, where one additional xarray walk is
always performed before termination.

Quit the loop once we get the last folio in the range, so the final
redundant xarray advancement can be avoided.

The xas_next() does not update xa_index when xas->xa_node is set to
XAS_RESTART, so the put and retry path would not update xa_index, hence
the warning should therefore never trigger.

During the 4k reads test, the overhead of this function dropped from 2.91%
to 2.53%.

Link: https://lore.kernel.org/20260620062446.351475-2-chizhiling@163.com
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Chi Zhiling <chizhiling@kylinos.cn>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:45 -07:00
JP Kobryn
094470f3f4 mm/lruvec: trace LRU add drains and drain-all requests 
LRU add batches can be drained before they reach capacity.  This can be a
source of LRU lock contention, but it is not currently possible to
attribute these drains to callers with existing tracepoints.

Add mm_lru_add_drain to report the CPU and lru_add batch count when an
lru_add batch is drained.  This allows tracing to distinguish full drains
from partial drains and attribute them to the calling stack.

Add mm_lru_add_drain_all to capture callers of __lru_add_drain_all and
whether they set the force flag for all CPUs.  The tracepoint resembles
the signature of the enclosing function, but is needed because of
potential inlining.

Note that DECLARE_TRACE() is used for these new trace hooks to avoid
creating a new trace event ABI.

Link: https://lore.kernel.org/20260622185127.24579-1-jp.kobryn@linux.dev
Signed-off-by: JP Kobryn <jp.kobryn@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:45 -07:00
Guopeng Zhang
4ac732c370 mm: memcg: remove stray text from obj_stock_pcp comment 
A patch filename was accidentally inserted into the comment describing
the nr_bytes field of struct obj_stock_pcp. Remove it.

No functional change.

Link: https://lore.kernel.org/20260623082614.81621-1-guopeng.zhang@linux.dev
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:45 -07:00
Igor Putko
253ed912fe mm/memory-failure: remove redundant initialization for hw_memory_failure 
The static variable 'hw_memory_failure' is implicitly initialized to
false.  Remove the explicit initialization to follow the Linux kernel
coding style.

Link: https://lore.kernel.org/20260623114743.4565-3-igorpetindev@gmail.com
Signed-off-by: Igor Putko <igorpetindev@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:44 -07:00
Igor Putko
731a624641 mm/kasan: remove redundant initialization for kasan_flag_write_only 
Patch series "mm: remove redundant static variable initializations".

This series removes explicit initializations of static bool variables to
false within the mm/ subsystem.  In C, static variables without explicit
initialization are implicitly placed in the .bss section and initialized
to zero/false by default.  Removing these explicit initializations follows
the Linux kernel coding style and avoids cluttering the data section.


This patch (of 2):

The static variable 'kasan_flag_write_only' is implicitly initialized to
false.  Remove the explicit initialization to follow the Linux kernel
coding style.

Link: https://lore.kernel.org/20260623114743.4565-1-igorpetindev@gmail.com
Link: https://lore.kernel.org/20260623114743.4565-2-igorpetindev@gmail.com
Signed-off-by: Igor Putko <igorpetindev@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:44 -07:00
Dev Jain
8a28b50d6f mm/mprotect: drop 'sub' from batching context 
Shorten the name of page_anon_exclusive_sub_batch by dropping the
"sub-batch" context - the function itself doesn't need this context. 
Similarly, drop "sub" from sub_batch_idx, it is unnecessary and the usage
is clear enough.

Link: https://lore.kernel.org/20260623125723.2503832-3-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:44 -07:00
Dev Jain
3ade884239 mm/swap: rename subpage->page in folio_dup_swap/folio_put_swap 
Patch series "mm: drop "sub" prefix from various places".

Patch 1 converts subpage->page : folios have pages, not subpages.

Patch 2 drops "sub" from a function and a variable because the context
is clear enough.


This patch (of 2):

Folios have pages, not subpages. Rename 'subpage' parameters to 'page'.

Link: https://lore.kernel.org/20260623125723.2503832-1-dev.jain@arm.com
Link: https://lore.kernel.org/20260623125723.2503832-2-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:44 -07:00
Zenghui Yu
7698d52e33 tools/mm: add thp_swap_allocator_test binary to .gitignore 
Tell git to ignore the generated binary for thp_swap_allocator_test.c.

Link: https://lore.kernel.org/20260624150642.19749-1-zenghui.yu@linux.dev
Signed-off-by: Zenghui Yu <zenghui.yu@linux.dev>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:43 -07:00
Joshua Hahn
ac0f3be693 mm/memcontrol: remove unused for_each_mem_cgroup macro and cleanup 
Commit 7e1c0d6f58 ("memcg: switch lruvec stats to rstat") removed the
last caller of for_each_mem_cgroup back in 2021, and there have not been
any new callers since.  Remove the macro.

A comment in mem_cgroup_css_online has also been out of date since 2021,
when 2bfd36374e ("mm: vmscan: consolidate shrinker_maps handling code")
open-coded the for_each_mem_cgroup iterator.  Update the comment.

Finally, 99430ab8b8 ("mm: introduce BPF kfuncs to access memcg
statistics and events") added a second declaration for memcg_events to
include/linux/memcontrol.h, duplicating the one in mm/memcontrol-v1.h. 
Let's clean that up too.

No functional changes intended.

Link: https://lore.kernel.org/20260624183700.1152742-1-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-28 21:11:43 -07:00
Linus Torvalds
62cc902415 13 hotfixes. All are cc:stable. 11 are for MM. All are singletons - 
please see the changelogs for details.
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Merge tag 'mm-hotfixes-stable-2026-07-27-14-18' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "13 hotfixes. All are cc:stable. 11 are for MM. All are singletons -
  please see the changelogs for details"

* tag 'mm-hotfixes-stable-2026-07-27-14-18' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  fs/proc/task_mmu: fix PAGEMAP_SCAN written state for PMD holes
  mm/hugetlb: fix list corruption in allocate_file_region_entries()
  mm: mglru: fix stale batch updates after memcg reparenting
  selftest: fix headers in fclog.c
  ocfs2: fix boundary check in ocfs2_check_dir_entry() to use buffer offset
  mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()
  mm/util: don't read __page_2 for order-1 folios in snapshot_page()
  mm/hugetlb: fix swap entry corruption when clearing uffd-wp at fork()
  mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE
  fs/proc/task_mmu: fix PAGEMAP_SCAN written state for unpopulated ptes
  userfaultfd: wait on source PMD during UFFDIO_MOVE
  lib: test_hmm: use device devt for coherent device range selection
  mm/vmstat: fold stranded per-cpu node stats when a node comes online
 2026-07-27 14:36:26 -07:00
Linus Torvalds
aa6fc3defb Hi 
This pull request contains bug fixes discussed in [1] and two fixes
 (in one commit) from Fabrice for DCP trusted keys backend..
 
 BR, Jarkko
 
 [1] https://lore.kernel.org/keyrings/amINZJVhEBwxEixP@kernel.org/
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Merge tag 'for-next-keys-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd

Pull keys fixes from Jarkko Sakkinen:

 - An unprivileged keyring whose keys collide through the
   description-chunk path can drive assoc_array node splitting
   into an out-of-bounds slot write. Fix it.

 - Fix the DCP trusted keys backend

* tag 'for-next-keys-7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
  assoc_array: trim the final shortcut word using the current chunk end
  keys: make keyring key-chunk byte order agree with keyring_diff_objects()
  keys: fix out-of-bounds read in keyring_get_key_chunk()
  KEYS: trusted: dcp: fix key_len validation and calc_blob_len() return type
 2026-07-27 14:14:11 -07:00
Linus Torvalds
e895a6fc20 Changes since the last update: 
- Keep a valid f_path for page cache sharing to fix a recent mincore()
    NULL pointer dereference
 
  - Limit LZMA stream pool size when too many processors are available
 
  - Sync up with Hongbo Li's latest email address
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Merge tag 'erofs-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "Fix a regression in page cache sharing which can cause a NULL pointer
  dereference, and limit LZMA stream memory usage on systems with many
  CPUs.

   - Keep a valid f_path for page cache sharing to fix a recent
     mincore() NULL pointer dereference

   - Limit LZMA stream pool size when too many processors are available

   - Sync up with Hongbo Li's latest email address"

* tag 'erofs-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: cap LZMA stream pool size
  erofs: ensure valid f_path for page cache sharing
  MAINTAINERS: update Hongbo Li's email address
 2026-07-27 09:31:44 -07:00
Linus Torvalds
e63c75f72f Pin control fixes for the v7.2 series: 
- Wakeup nits on the Qualcomm SC8280XP.
 
 - Double-free issues on the device tree parsing error path.
 
 - Fixup of the S4 sleep state handling on AMD pin control.
 
 - Missing Kconfig select REGMAP_MMIO for the Microchip
   driver leading to compile stalls.
 
 - Missing Kconfig select GENERIC_PINCONF for the Bitmain
   BM1880 leading to compile stalls.
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Merge tag 'pinctrl-v7.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl

Pull pin control fixes from Linus Walleij:
 "The most interesting commit is the S4 fix for AMD, which probably is
  helpful to a whole bunch of important machines.

   - Wakeup nits on the Qualcomm SC8280XP

   - Double-free issues on the device tree parsing error path

   - Fixup of the S4 sleep state handling on AMD pin control

   - Missing Kconfig select REGMAP_MMIO for the Microchip driver leading
     to compile stalls

   - Missing Kconfig select GENERIC_PINCONF for the Bitmain BM1880
     leading to compile stalls"

* tag 'pinctrl-v7.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: bm1880: add missing select GENERIC_PINCONF
  pinctrl-amd: Don't clear S4 wake bits at probe
  pinctrl: microchip-sgpio: add missing select REGMAP_MMIO
  pinctrl: devicetree: don't free uninitialized dev_name on error path
  pinctrl: qcom: sc8280xp: Add missing wakeup entries for GPIO143/151
  pinctrl: qcom: Unconditionally mark gpio as wakeup enable
 2026-07-27 08:48:48 -07:00
Michael Bommarito
c9b47e6b23 erofs: cap LZMA stream pool size 
fs/erofs/decompressor_lzma.c sizes the module-global MicroLZMA stream
pool from num_possible_cpus() when the lzma_streams module parameter is
unset, then z_erofs_load_lzma_config() preallocates one image-supplied
dictionary per stream, accepting dictionaries up to 8 MiB.  On high-CPU
systems, a small EROFS image can pin hundreds of MiB of vmalloc-backed
decoder state until the erofs module is unloaded.

Impact: An EROFS image mounted by the system can pin up to 8 MiB of
vmalloc memory per LZMA stream, either as intended or unexpectedly.

Bound the default stream count by a new
CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS option, default 16, so the
worst-case default preallocation is 128 MiB if the number of CPUs is no
less than 16 while preserving the existing per-image dictionary limit.
An explicit lzma_streams module parameter is still honoured as-is, so
administrators who deliberately size the pool are not affected.

Fixes: 622ceaddb7 ("erofs: lzma compression support")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
 2026-07-27 12:31:11 +08:00
Gao Xiang
96b2dbbe58 erofs: ensure valid f_path for page cache sharing 
Previously, backing files for page cache sharing were set up with
f_path left as NULL (only f_inode was valid).  It worked, but a recent
mincore fix relies on f_path.mnt and crashes (found by "erofs/028" on
7.2-rc4):

 BUG: kernel NULL pointer dereference, address: 0000000000000018
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] SMP PTI
 CPU: 3 UID: 0 PID: 675528 Comm: fincore Not tainted 7.2.0-rc4-00002-g[]-dirty #1 PREEMPT(lazy)
 Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014
 RIP: 0010:__do_sys_mincore+0xc0/0x2c0
 ...

Specify valid paths using valid disconnected dentries together with
erofs_ishare_mnt instead of leaving f_path empty, so they are more
like real backing files in a pseudo filesystem and standard
backing_file_open() can be used directly.

Fixes: e187bc02f8 ("mm: do file ownership checks with the proper mount idmap")
Acked-by: Hongbo Li <hongbohbli@tencent.com>
Signed-off-by: Gao Xiang <xiang@kernel.org>
 2026-07-27 12:31:02 +08:00
Linus Torvalds
f5098b6bae Linux 7.2-rc5 v7.2-rc5 2026-07-26 14:45:48 -07:00
Linus Torvalds
4235cb24ec vfs-7.2-rc5.fixes 
Please consider pulling these changes from the signed vfs-7.2-rc5.fixes tag.
 
 Thanks!
 Christian
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Merge tag 'vfs-7.2-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - vfs: Preserve the ACL_DONT_CACHE state in forget_cached_acl().

   ACL_DONT_CACHE is meant to be a permanent opt-out from ACL caching
   which FUSE relies on for servers that don't negotiate FUSE_POSIX_ACL.
   The helper replaced it with ACL_NOT_CACHED, silently re-enabling the
   cache, and as fuse doesn't invalidate the cache for such servers a
   properly timed get_acl() returned stale ACLs. Comes with a fuse
   selftest reproducing this.

 - pidfs:

     - Preserve PIDFD_THREAD when a thread pidfd is reopened via
       open_by_handle_at(). PIDFD_THREAD shares the O_EXCL bit which
       do_dentry_open() strips after the flags have been validated, so
       the reopened pidfd silently became a process pidfd. Comes with a
       selftest.

     - Add a pidfs_dentry_open() helper so the regular pidfd allocation
       path and the file handle path share the code that forces O_RDWR
       and reapplies the pidfd flags that do_dentry_open() strips.

     - Handle FS_IOC32_GETVERSION in the compat ioctl path.

     - Make pidfs_ino_lock static.

 - iomap:

     - Fix the block range calculation in ifs_clear_range_dirty() so a
       partial clear doesn't drop the dirty state of blocks the range
       only partially covers.

     - Support invalidating partial folios so a partial truncate or hole
       punch with blocksize < foliosize doesn't leave stale dirty bits
       behind.

     - Only set did_zero when iomap_zero_iter() actually zeroed
       something.

     - Guard ifs_set_range_dirty() and ifs_set_range_uptodate() against
       zero-length ranges where the unsigned last-block calculation
       underflows and bitmap_set() writes far beyond the ifs->state
       allocation.

     - Don't merge ioends with different io_private values as the merge
       could leak or corrupt the private data of the individual ioends.

 - exec:

     - Raise bprm->have_execfd only once the binfmt_misc interpreter has
       actually been opened. The flag was set as soon as a matching 'O'
       or 'C' entry was found. If the interpreter open failed with
       ENOEXEC the exec fell through to the next binary format with
       have_execfd raised but no executable staged and begin_new_exec()
       NULL derefed past the point of no return.

     - Fix an unsigned loop counter wrap in transfer_args_to_stack() on
       nommu. An overlong argument or environment string pushes bprm->p
       below PAGE_SIZE, the stop index becomes zero, and the loop never
       terminates, wrapping its counter and copying garbage from in
       front of the page array into the new process stack.

     - Make binfmt_elf_fdpic only honour the first PT_INTERP like
       binfmt_elf does. Each additional PT_INTERP overwrote the previous
       interpreter, leaking the name allocation and the interpreter file
       reference together with the write denial open_exec() took,
       leaving the file unwritable for as long as the system runs.

 - overlayfs:

     - Compare the full escaped xattr prefix including the trailing dot.
       An xattr like "trusted.overlay.overlayfoo" was misclassified as
       an escaped overlay xattr.

     - Check read access to the copy_file_range() source with the
       source's mounter credentials.

 - super: Thawing a filesystem whose block device was frozen with
   bdev_freeze() deadlocked. Dropping the last block layer freeze
   reference from under s_umount ends up in fs_bdev_thaw() which
   reacquires s_umount on the same task. Pin the superblock with an
   active reference instead and call bdev_thaw() without holding
   s_umount.

 - procfs: Return EACCES instead of success when the ptrace access check
   for namespace links fails.

 - afs: Use afs_dir_get_block() rather than afs_dir_find_block() for
   block 0 in afs_edit_dir_remove(), matching afs_edit_dir_add().

 - Push the memcg gating of ->nr_cached_objects() down into the btrfs
   and shmem callbacks instead of skipping every callback during
   non-root memcg reclaim. The blanket check short-circuited XFS whose
   inode reclaim hook is intentionally driven from per-memcg contexts to
   free memcg-charged slab.

 - eventpoll: Pin files while checking reverse paths.

   Since struct file became SLAB_TYPESAFE_BY_RCU a concurrent close
   could free and recycle the file under the check which then took and
   dropped the f_lock of whatever live file now occupies that slot.

* tag 'vfs-7.2-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
  super: fix emergency thaw deadlock on frozen block devices
  pidfs: make pidfs_ino_lock static
  eventpoll: pin files while checking reverse paths
  fs: push nr_cached_objects memcg gating into individual filesystems
  afs: Fix afs_edit_dir_remove() to get, not find, block 0
  iomap: prevent ioend merge when io_private differs
  iomap: add comments for ifs_clear/set_range_dirty()
  iomap: fix out-of-bounds bitmap_set() with zero-length range
  iomap: fix incorrect did_zero setting in iomap_zero_iter()
  iomap: support invalidating partial folios
  iomap: correct the range of a partial dirty clear
  fs/super: fix emergency thaw double-unlock of s_umount
  pidfs: handle FS_IOC32_GETVERSION in compat ioctl
  ovl: check access to copy_file_range source with src mounter creds
  proc: Fix broken error paths for namespace links
  pidfs: add pidfs_dentry_open() helper
  selftests/pidfd: check PIDFD_THREAD survives open_by_handle_at()
  pidfs: preserve thread pidfds reopened by file handle
  ovl: fix trusted xattr escape prefix matching
  selftests/fuse: add ACL_DONT_CACHE regression test
  ...
 2026-07-26 12:22:57 -07:00
Linus Torvalds
72841e8e83 spi: Fixes for v7.2 
Just a couple of small bits for the SpacemiT driver - one small fix, and
 a new compatible in the DT binding.
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Merge tag 'spi-fix-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi fixes from Mark Brown:
 "Just a couple of small bits for the SpacemiT driver - one small fix,
  and a new compatible in the DT binding"

* tag 'spi-fix-v7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: dt-bindings: spacemit: add K3 SPI compatible
  spi: spacemit: Correct TX FIFO slot calculation
 2026-07-26 12:13:42 -07:00