Pull cgroup fixes from Tejun Heo:

 - After cgroup.kill was written to a cgroup, every child cloned into it
   with CLONE_INTO_CGROUP was spuriously killed because the fork path
   snapshotted the kill counter before resolving the target cgroup

 - Releasing an isolated cpuset partition dropped the isolation of CPUs
   isolated on the kernel command line

 - Selftest and documentation fixes

* tag 'cgroup-for-7.3-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  selftests/cgroup: test clone3() into a previously killed cgroup
  cgroup: fix spurious SIGKILL of CLONE_INTO_CGROUP children
  selftests/cgroup: Add test for preserving boot-isolated CPUs
  cgroup/cpuset: Preserve boot-isolated CPUs on partition release
  selftests/cgroup: Drop invalid boot isolation comparison
  docs: cgroup-v2: fix misc.events key format description
  selftests/cgroup: Fix cg_run_in_subcgroups ignoring arg parameter
  selftests/cgroup: set the test plan after the setup checks

Once cgroup.kill had been written to a cgroup, a stale kill_seq
snapshot (taken in cgroup_css_set_fork() before the target cgroup was
resolved) caused every child subsequently cloned into that cgroup with
clone3(CLONE_INTO_CGROUP) to be SIGKILLed on the spot.

Add a regression test: create a cgroup, kill it while it is empty,
then clone a child into it and check that the child runs and exits
cleanly. On a kernel without the fix, the test fails:

  not ok 4 test_cgkill_clone_into_killed

The test is skipped on kernels without clone3() or without
CLONE_INTO_CGROUP.

Cc: Shakeel Butt <shakeel.butt@linux.dev>
Assisted-by: LLM
Signed-off-by: Etienne Perot <eperot@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull more MM updates from Andrew Morton:

 - "mm/rmap: index MAP_PRIVATE file-backed folios by anonymous pgoff"
   (Lorenzo Stoakes)

   Index MAP_PRIVATE file-backed folios by their anonymous page offset
   to resolve confusion around reverse mapping for zeroed and CoW'd
   file-backed memory.

   Use this new VMA anonymous page offset tracking to eliminate index
   conflicts and lay the foundation for scalable CoW performance
   improvements.

 - "promote mapped executable folios after first usage for MGLRU"
   (Baolin Wang)

   Make MGLRU's protection of mapped executable file folios more
   reliable. Follow the classical LRU's logic, promoting mapped
   executable file folios after their first usage to give executable
   code a better chance to stay in memory and improve workload
   performance.

 - "mm: vmscan: fix node reclaim ignoring swappiness parameter" (Ridong
   Chen)

   Fix per-node proactive reclaim interface's ignoring the swappiness
   parameter when CONFIG_MEMCG is disabled by consolidating
   sc_swappiness() into a single function that checks
   proactive_swappiness regardless of kernel configuration.

 - "mm/vmscan: reduce lru_lock contention via vmstat-derived
   scan-balance cost" (Usama Arif)

   Reduce lru_lock contention in the reclaim path by deriving
   scan-balance costs from vmstat counters rather than lock-acquired
   producer updates.

   Read and decay these cost signals on the reclaim side under a
   dedicated per-lruvec lock, reducing total LRU lock wait time by over
   60% without impacting scan throughput.

 - "zram: fix zram issues reported by sashiko" (Sergey Senozhatsky)

   Fix two low-risk zram bugs which Sashiko spotted in drive-by review.

 - "Honor XA_FLAGS_ACCOUNT in xas_split_alloc() and charge to folio's
   memcg" (Zi Yan)

   Fix xas_split_alloc() by enabling target folio memcg charging during
   splits and adding the missing __GFP_ACCOUNT flag for proper XArray
   node memory accounting.

 - "selftests/mm: use pattern matching in .gitignore" (Pratyush Mallick)

   Replace hardcoded binary names in selftests/mm/.gitignore with a
   generic pattern-matching rule to automatically ignore generated test
   files and avoid manual updates when adding new tests.

 - "mm/page_ext: remove pgdat_page_ext_init()" (Sang-Heon Jeon)

   Make the incompatibility between FLATMEM and NUMA explicit in
   mm/Kconfig and remove the unused pgdat_page_ext_init() function.

 - "zram: fix zstd error paths and add parameter validation" (Haoqin
   Huang)

   Clean up zram compression backends by removing redundant error
   cleanup, adding parameter and dictionary validation, auto-prefixing
   algorithm error logs, and resetting parameters prior to
   reinitialization.

 - "zram: fix stale scan bounds after reinitialization" (Longlong Xia)

   Prevent out-of-bounds slot accesses during concurrent zram resets by
   moving table scan bound calculations under dev_lock in
   writeback_store() and read_block_state().

 - "add anon mTHP collapse test cases" (Baolin Wang)

   Extend selftests helper functions to support arbitrary page orders
   and add new test cases and options for mTHP collapse in khugepaged.

 - "selftests/mm: Handle unsupported and transient test conditions"
   (Muhammad Usama Anjum)

   Update MM selftests to report a SKIP status instead of a failure when
   required kernel or filesystem features are unsupported, while adding
   retry logic for transient page migration errors.

 - "mm/zswap: Fixes and improves the zswap shrink" (Hao Jia)

   Fix the missing zswap global shrinker when CONFIG_MEMCG is disabled
   and extend shrink_memcg() to support batch writeback for improved
   writeback efficiency.

 - "alloc_tag: introduce IOCTL-based filtering for MAP" (Suren
   Baghdasaryan)

   Introduce an IOCTL-based binary interface for memory allocation
   profiling that enables kernel-side filtering before per-CPU counter
   aggregation.

   This eliminates the text-parsing overhead of /proc/allocinfo and
   provides up to a 20x speedup by transferring only filtered allocation
   data to userspace.

 - "better block swap batching and a different take on swap_ops v5"
   (Christoph Hellwig)

   Refactor block swap I/O to use swap_iocb for batching instead of
   single-bio requests and rebase the swap_ops interface, achieving
   faster swap throughput during kernel builds.

 - "mm: kmemleak: reduce transient false positives by confirming leaks"
   (Catalin Marinas)

   Reduce false-positive kmemleak reports by combining two kmemleak
   enhancements that add a second confirmation scan and a configurable
   minimum unreferenced scan count module parameter.

 - "mm: kmemleak: default min_unref_scans to 2 for verbose kernels"
   (Breno Leitao)

   Auto-scanning kernels can generate false-positive memory leak reports
   on single scans, so this patch defaults min_unref_scans to 2 when
   CONFIG_DEBUG_KMEMLEAK_VERBOSE is enabled to require a second
   confirming scan.

 - "swap_ops updates" (Christoph Hellwig)

   Batching I/O for synchronous swap devices causes performance
   regressions and filesystem-based swap suffers from double-indirection
   overhead. This series resolves both issues by reintroducing per-folio
   writes for synchronous swap and allowing filesystems to directly
   export their own swap_ops.

 - "mm/khugepaged: several cleanups" (Nico Pache)

   khugepaged accumulated redundant state-checking patterns and outdated
   comments following mTHP integration. Introduce dedicated helpers for
   PTE validation and event counting while refreshing the internal
   documentation.

 - "maple_tree: lock checking and clean ups" (Liam Howlett)

   Syzbot reports incorrectly blame memory management exit paths for
   locking bugs, maple tree erase operations risk allocation failures
   without gfp flags and internal documentation lacks clarity.

   Improve lock error detection, update docs, fix race and allocation
   edge cases and optimize erase allocations using a fallback to
   GFP_KERNEL | GFP_NOFAIL.

* tag 'mm-stable-2026-08-26-15-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (172 commits)
  selftests/proc: make proc-maps-race work with READ_IMPLIES_EXEC
  memcg: move LRU size accounting on reparenting instead of copying it
  mm/vmscan: fix comment logic in balance_pgdat
  maple_tree: add helper mas_make_walkable()
  maple_tree: avoid extra gap calculation
  maple_tree: fix argument name in header
  maple_tree: change two GFP flags in tests
  maple_tree: document erase and allocations better
  maple_tree: avoid mas_erase() and mtree_erase() failures
  maple_tree: document that erase may use GFP_KERNEL for allocations
  maple_tree: catch race in mas_alloc_cyclic()
  maple_tree: add bulk parent set helper
  maple_tree: micro optimisation of mas_wr_store_type()
  maple_tree: optimise mas_wr_node_store() when not in rcu mode
  maple_tree: use prefetched value in mas_wr_store_type()
  maple_tree: clarify comments on mas_nomem()
  maple_tree: drop MAPLE_ALLOC_SLOTS
  maple_tree: drop dead code from mas_extend_spanning_null()
  maple_tree: documentation fix
  maple_tree: add write lock checking with lockdep sequence numbers
  ...

test_no_kmem_bypass() needs to read /sys/kernel/debug/zswap/stored_pages
via get_zswap_stored_pages() to verify that compressed pages are charged
to the memcg.

When running in an environment where debugfs is not mounted or
CONFIG_DEBUG_FS is disabled, get_zswap_stored_pages() fails, causing the
loop to terminate early and report a false negative (KSFT_FAIL).

Selftests should not fail if debugfs is unavailable, and it should print a
message when it is skipped.

While I'm here, also add a warning message if the test is being skipped
due to totalram size and make the check for totalram more readable.

[akpm@linux-foundation.org: clarify debugfs-unavailable error message]
Link: https://lore.kernel.org/20260812050848.848882-1-wfelipe@google.com
Link: https://lore.kernel.org/20260811051434.3805648-1-wfelipe@google.com
Signed-off-by: Wilson Felipe Pereira <wfelipe@google.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Put a CPU isolated at boot into an isolated partition, change the
partition back to member and check that the CPU remains isolated.

Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

check_isolcpus() clears ISOLCPUS before rebuilding it from sched domain
data. Comparing that empty value with
/sys/devices/system/cpu/isolated makes the test fail whenever
isolcpus=domain is present.

That sysfs file is generated from HK_TYPE_DOMAIN_BOOT and does not change
when cpuset updates HK_TYPE_DOMAIN. Re-reading it cannot validate dynamic
housekeeping updates. The cpuset.cpus.isolated and sched domain checks
already cover the two dynamic interfaces, so remove the invalid comparison.

This can be reproduced on a kernel booted with isolcpus=domain,15:

    # tools/testing/selftests/cgroup/test_cpuset_prs.sh

The test fails its first state-matrix isolation check before the change and
continues past that check afterward.

Fixes: 6df415aa46ec ("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue")
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

cg_run_in_subcgroups() discards its arg and always passes NULL to cg_run(),
turning the (void *)100 from test_kmem_dead_cgroups() into NULL so no
allocation occurs.

This makes test_kmem_dead_cgroups() falsely pass without exercising the
"dying cgroup with charged slab" scenario it intends to test.

Pass the arg through to cg_run() to fix this.

Fixes: 933dc80ec262 ("kselftests: cgroup: add kernel memory accounting tests")
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

The cgroup tests announce their plan before checking whether cgroup v2 is
available, so on a host without it they promise a number of results and
then skip out after the first one:

	TAP version 13
	1..3
	ok 1 # SKIP cgroup v2 isn't mounted
	# Planned tests != run tests (3 != 1)
	# Totals: pass:0 fail:0 xfail:0 xpass:0 skip:1 error:0

ksft_exit_skip() can only emit a well formed "1..0 # SKIP" line while no
plan has been printed, as the comment above it in kselftest.h points out.

Move ksft_set_plan() below the setup checks that can skip, so that a
skipped run reports:

	TAP version 13
	1..0 # SKIP cgroup v2 isn't mounted

Several of the tests skip more than once while setting up, for a missing
or unwritable controller as well, so the plan goes after the last of
them.  test_core joins its two setup paths at the post_v2_setup label and
sets the plan there.

Reporting each planned test as skipped instead would keep the plan where
it is, but the setup failures here mean the whole test cannot run rather
than its individual cases being skipped, which is what "1..0 # SKIP" is
for.

Fixes: 1dc830ee4c15 ("selftests/cgroup: conform test to KTAP format output")
Signed-off-by: Hemanth Selam <hemanth.selam@gmail.com>
Reviewed-by: Sarthak Sharma <sarthak.sharma@arm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

test_cgcore_lesser_ns_open runs as root throughout and never changes its
euid, so chowning the two cgroup.procs files to a non-root uid has no
effect on the test.

The ENOENT the test expects comes from the cgroup namespace delegation
check in cgroup_procs_write_permission(): the source and destination
cgroups must both be descendants of the namespace root captured at open
time.  That check does not depend on file ownership.  In addition, the
permission check only examines the common ancestor's cgroup.procs file
(the test root here), which the chown calls do not touch.

Remove the redundant chown calls and the now unused test_euid and
cg_test_a_procs variables.

Signed-off-by: Shaojie Sun <sunshaojie@kylinos.cn>
Reviewed-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>

The cpuset partition root state selftest checks several CPU hotplug
transitions. If writing to a CPU online file fails, the helper still
runs pause afterwards and returns the status of pause instead of the
failed write.

This hides the real hotplug failure and can make later checks run
against expectations for a transition that never happened. Move the
write before the bookkeeping and return when it fails, so callers can
observe the hotplug error and the test does not record a CPU as offline
unless the offline operation actually succeeded.

Also change the O* command handler in set_ctrl_state() to use
"eval $COMM $REDIRECT" like all other handlers. The previous version
set COMM but still called write_cpu_online directly, bypassing the
redirect that captures stderr for error reporting.

Changes since v1:
 - Use eval $COMM $REDIRECT in the O* handler instead of calling
   write_cpu_online directly (Waiman Long)

Fixes: a8c52eba880a ("kselftest/cgroup: Add cpuset v2 partition root state test")
Signed-off-by: Rui Qi <qirui.001@bytedance.com>
Signed-off-by: Tejun Heo <tj@kernel.org>