<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/kernel/events, branch v6.15</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v6.15</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v6.15'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2025-04-23T07:39:06Z</updated>
<entry>
<title>perf/core: Change to POLLERR for pinned events with error</title>
<updated>2025-04-23T07:39:06Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2025-04-22T22:33:18Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=0db61388b389f43c1ba2f1cee3613feb4fd12150'/>
<id>urn:sha1:0db61388b389f43c1ba2f1cee3613feb4fd12150</id>
<content type='text'>
Commit:

  f4b07fd62d4d11d5 ("perf/core: Use POLLHUP for pinned events in error")

started to emit POLLHUP for pinned events in an error state.

But the POLLHUP is also used to signal events that the attached task is
terminated.  To distinguish pinned per-task events in the error state
it would need to check if the task is live.

Change it to POLLERR to make it clear.

Suggested-by: Gabriel Marin &lt;gmx@google.com&gt;
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20250422223318.180343-1-namhyung@kernel.org
</content>
</entry>
<entry>
<title>perf: Fix hang while freeing sigtrap event</title>
<updated>2025-04-08T18:55:43Z</updated>
<author>
<name>Frederic Weisbecker</name>
<email>frederic@kernel.org</email>
</author>
<published>2025-03-04T13:54:46Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=56799bc035658738f362acec3e7647bb84e68933'/>
<id>urn:sha1:56799bc035658738f362acec3e7647bb84e68933</id>
<content type='text'>
Perf can hang while freeing a sigtrap event if a related deferred
signal hadn't managed to be sent before the file got closed:

perf_event_overflow()
   task_work_add(perf_pending_task)

fput()
   task_work_add(____fput())

task_work_run()
    ____fput()
        perf_release()
            perf_event_release_kernel()
                _free_event()
                    perf_pending_task_sync()
                        task_work_cancel() -&gt; FAILED
                        rcuwait_wait_event()

Once task_work_run() is running, the list of pending callbacks is
removed from the task_struct and from this point on task_work_cancel()
can't remove any pending and not yet started work items, hence the
task_work_cancel() failure and the hang on rcuwait_wait_event().

Task work could be changed to remove one work at a time, so a work
running on the current task can always cancel a pending one, however
the wait / wake design is still subject to inverted dependencies when
remote targets are involved, as pictured by Oleg:

T1                                                      T2

fd = perf_event_open(pid =&gt; T2-&gt;pid);                  fd = perf_event_open(pid =&gt; T1-&gt;pid);
close(fd)                                              close(fd)
    &lt;IRQ&gt;                                                  &lt;IRQ&gt;
    perf_event_overflow()                                  perf_event_overflow()
       task_work_add(perf_pending_task)                        task_work_add(perf_pending_task)
    &lt;/IRQ&gt;                                                 &lt;/IRQ&gt;
    fput()                                                 fput()
        task_work_add(____fput())                              task_work_add(____fput())

    task_work_run()                                        task_work_run()
        ____fput()                                             ____fput()
            perf_release()                                         perf_release()
                perf_event_release_kernel()                            perf_event_release_kernel()
                    _free_event()                                          _free_event()
                        perf_pending_task_sync()                               perf_pending_task_sync()
                            rcuwait_wait_event()                                   rcuwait_wait_event()

Therefore the only option left is to acquire the event reference count
upon queueing the perf task work and release it from the task work, just
like it was done before 3a5465418f5f ("perf: Fix event leak upon exec and file release")
but without the leaks it fixed.

Some adjustments are necessary to make it work:

* A child event might dereference its parent upon freeing. Care must be
  taken to release the parent last.

* Some places assuming the event doesn't have any reference held and
  therefore can be freed right away must instead put the reference and
  let the reference counting to its job.

Reported-by: "Yi Lai" &lt;yi1.lai@linux.intel.com&gt;
Closes: https://lore.kernel.org/all/Zx9Losv4YcJowaP%2F@ly-workstation/
Reported-by: syzbot+3c4321e10eea460eb606@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/673adf75.050a0220.87769.0024.GAE@google.com/
Fixes: 3a5465418f5f ("perf: Fix event leak upon exec and file release")
Signed-off-by: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20250304135446.18905-1-frederic@kernel.org
</content>
</entry>
<entry>
<title>uprobes: Avoid false-positive lockdep splat on CONFIG_PREEMPT_RT=y in the ri_timer() uprobe timer callback, use raw_write_seqcount_*()</title>
<updated>2025-04-07T18:15:16Z</updated>
<author>
<name>Andrii Nakryiko</name>
<email>andrii@kernel.org</email>
</author>
<published>2025-04-04T19:48:48Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=0cd575cab10e114e95921321f069a08d45bc412e'/>
<id>urn:sha1:0cd575cab10e114e95921321f069a08d45bc412e</id>
<content type='text'>
Avoid a false-positive lockdep warning in the CONFIG_PREEMPT_RT=y
configuration when using write_seqcount_begin() in the uprobe timer
callback by using raw_write_* APIs.

Uprobe's use of timer callback is guaranteed to not race with itself
for a given uprobe_task, and as such seqcount's insistence on having
preemption disabled on the writer side is irrelevant. So switch to
raw_ variants of seqcount API instead of disabling preemption unnecessarily.

Also, point out in the comments more explicitly why we use seqcount
despite our reader side being rather simple and never retrying. We favor
well-maintained kernel primitive in favor of open-coding our own memory
barriers.

Fixes: 8622e45b5da1 ("uprobes: Reuse return_instances between multiple uretprobes within task")
Reported-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Suggested-by: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20250404194848.2109539-1-andrii@kernel.org
</content>
</entry>
<entry>
<title>perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init</title>
<updated>2025-04-06T18:30:28Z</updated>
<author>
<name>Gabriel Shahrouzi</name>
<email>gshahrouzi@gmail.com</email>
</author>
<published>2025-04-05T20:30:36Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=0ba3a4ab76fd3367b9cb680cad70182c896c795c'/>
<id>urn:sha1:0ba3a4ab76fd3367b9cb680cad70182c896c795c</id>
<content type='text'>
Move the get_ctx(child_ctx) call and the child_event-&gt;ctx assignment to
occur immediately after the child event is allocated. Ensure that
child_event-&gt;ctx is non-NULL before any subsequent error path within
inherit_event calls free_event(), satisfying the assumptions of the
cleanup code.

Details:

There's no clear Fixes tag, because this bug is a side-effect of
multiple interacting commits over time (up to 15 years old), not
a single regression.

The code initially incremented refcount then assigned context
immediately after the child_event was created. Later, an early
validity check for child_event was added before the
refcount/assignment. Even later, a WARN_ON_ONCE() cleanup check was
added, assuming event-&gt;ctx is valid if the pmu_ctx is valid.
The problem is that the WARN_ON_ONCE() could trigger after the initial
check passed but before child_event-&gt;ctx was assigned, violating its
precondition. The solution is to assign child_event-&gt;ctx right after
its initial validation. This ensures the context exists for any
subsequent checks or cleanup routines, resolving the WARN_ON_ONCE().

To resolve it, defer the refcount update and child_event-&gt;ctx assignment
directly after child_event-&gt;pmu_ctx is set but before checking if the
parent event is orphaned. The cleanup routine depends on
event-&gt;pmu_ctx being non-NULL before it verifies event-&gt;ctx is
non-NULL. This also maintains the author's original intent of passing
in child_ctx to find_get_pmu_context before its refcount/assignment.

[ mingo: Expanded the changelog from another email by Gabriel Shahrouzi. ]

Reported-by: syzbot+ff3aa851d46ab82953a3@syzkaller.appspotmail.com
Signed-off-by: Gabriel Shahrouzi &lt;gshahrouzi@gmail.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20250405203036.582721-1-gshahrouzi@gmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ff3aa851d46ab82953a3
</content>
</entry>
<entry>
<title>Merge tag 'perf-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2025-04-06T17:48:12Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-06T17:48:12Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=dda8887894965369a87ba27320f6b337c4cd9e12'/>
<id>urn:sha1:dda8887894965369a87ba27320f6b337c4cd9e12</id>
<content type='text'>
Pull perf event fix from Ingo Molnar:
 "Fix a perf events time accounting bug"

* tag 'perf-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix child_total_time_enabled accounting bug at task exit
</content>
</entry>
<entry>
<title>mseal sysmap: uprobe mapping</title>
<updated>2025-04-01T22:17:16Z</updated>
<author>
<name>Jeff Xu</name>
<email>jeffxu@chromium.org</email>
</author>
<published>2025-03-05T02:17:09Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=3d38922abff330ec2ec8d0d6d38b647d121a0be9'/>
<id>urn:sha1:3d38922abff330ec2ec8d0d6d38b647d121a0be9</id>
<content type='text'>
Provide support to mseal the uprobe mapping.

Unlike other system mappings, the uprobe mapping is not established during
program startup.  However, its lifetime is the same as the process's
lifetime.  It could be sealed from creation.

Test was done with perf tool, and observe the uprobe mapping is sealed.

Link: https://lkml.kernel.org/r/20250305021711.3867874-6-jeffxu@google.com
Signed-off-by: Jeff Xu &lt;jeffxu@chromium.org&gt;
Reviewed-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Reviewed-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Reviewed-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Reviewed-by: Kees Cook &lt;kees@kernel.org&gt;
Cc: Adhemerval Zanella &lt;adhemerval.zanella@linaro.org&gt;
Cc: Alexander Mikhalitsyn &lt;aleksandr.mikhalitsyn@canonical.com&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Anna-Maria Behnsen &lt;anna-maria@linutronix.de&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Benjamin Berg &lt;benjamin@sipsolutions.net&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Elliot Hughes &lt;enh@google.com&gt;
Cc: Florian Faineli &lt;f.fainelli@gmail.com&gt;
Cc: Greg Ungerer &lt;gerg@kernel.org&gt;
Cc: Guenter Roeck &lt;groeck@chromium.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Hyeonggon Yoo &lt;42.hyeyoo@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jason A. Donenfeld &lt;jason@zx2c4.com&gt;
Cc: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Cc: Jorge Lucangeli Obes &lt;jorgelo@chromium.org&gt;
Cc: Linus Waleij &lt;linus.walleij@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Matthew Wilcow (Oracle) &lt;willy@infradead.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Mike Rapoport &lt;mike.rapoport@gmail.com&gt;
Cc: Pedro Falcato &lt;pedro.falcato@gmail.com&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Stephen Röttger &lt;sroettger@google.com&gt;
Cc: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2025-04-01T16:29:18Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-01T16:29:18Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=eb0ece16027f8223d5dc9aaf90124f70577bd22a'/>
<id>urn:sha1:eb0ece16027f8223d5dc9aaf90124f70577bd22a</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - The series "Enable strict percpu address space checks" from Uros
   Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.

   This has caused a small amount of fallout - two or three issues were
   reported. In all cases the calling code was found to be incorrect.

 - The series "Some cleanup for memcg" from Chen Ridong implements some
   relatively monir cleanups for the memcontrol code.

 - The series "mm: fixes for device-exclusive entries (hmm)" from David
   Hildenbrand fixes a boatload of issues which David found then using
   device-exclusive PTE entries when THP is enabled. More work is
   needed, but this makes thins better - our own HMM selftests now
   succeed.

 - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
   remove the z3fold and zbud implementations. They have been deprecated
   for half a year and nobody has complained.

 - The series "mm: further simplify VMA merge operation" from Lorenzo
   Stoakes implements numerous simplifications in this area. No runtime
   effects are anticipated.

 - The series "mm/madvise: remove redundant mmap_lock operations from
   process_madvise()" from SeongJae Park rationalizes the locking in the
   madvise() implementation. Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.

 - The series "Tiny cleanup and improvements about SWAP code" from
   Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.

 - The series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak
   user-visible output.

 - The series "mm/damon/paddr: fix large folios access and schemes
   handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.

 - The series "mm/damon/core: fix wrong and/or useless damos_walk()
   behaviors" from SeongJae Park fixes a few issues with the accuracy of
   kdamond's walking of DAMON regions.

 - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
   Stoakes changes the interaction between framebuffer deferred-io and
   core MM. No functional changes are anticipated - this is preparatory
   work for the future removal of page structure fields.

 - The series "mm/damon: add support for hugepage_size DAMOS filter"
   from Usama Arif adds a DAMOS filter which permits the filtering by
   huge page sizes.

 - The series "mm: permit guard regions for file-backed/shmem mappings"
   from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state. The feature now covers shmem and
   file-backed mappings.

 - The series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping
   for pte-mapped large folios.

 - The series "reimplement per-vma lock as a refcount" from Suren
   Baghdasaryan puts the vm_lock back into the vma. Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy. This patchset provides small (0-10%) improvements on one
   microbenchmark.

 - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
   improves" from SeongJae Park does some maintenance work on the DAMON
   docs.

 - The series "hugetlb/CMA improvements for large systems" from Frank
   van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.

 - The series "mm/damon: introduce DAMOS filter type for unmapped pages"
   from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.

 - The series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.

 - The series "selftests/mm: Some cleanups from trying to run them" from
   Brendan Jackman fixes a pile of unrelated issues which Brendan
   encountered while runnimg our selftests.

 - The series "fs/proc/task_mmu: add guard region bit to pagemap" from
   Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.

 - The series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply
   wasn't being effective.

 - The series "mm: cleanups for device-exclusive entries (hmm)" from
   David Hildenbrand implements a number of unrelated cleanups in this
   code.

 - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
   implements a number of preparatoty cleanups to the GENERIC_PTDUMP
   Kconfig logic.

 - The series "mm/damon: auto-tune aggregation interval" from SeongJae
   Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.

 - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
   powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
   preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.

 - The series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the
   code easier to follow.

 - The series "page_counter cleanup and size reduction" from Shakeel
   Butt cleans up the page_counter code and fixes a size increase which
   we accidentally added late last year.

 - The series "Add a command line option that enables control of how
   many threads should be used to allocate huge pages" from Thomas
   Prescher does that. It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.

 - The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
   from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.

 - The series "mm/damon: make allow filters after reject filters useful
   and intuitive" from SeongJae Park improves the handling of allow and
   reject filters. Behaviour is made more consistent and the documention
   is updated accordingly.

 - The series "Switch zswap to object read/write APIs" from Yosry Ahmed
   updates zswap to the new object read/write APIs and thus permits the
   removal of some legacy code from zpool and zsmalloc.

 - The series "Some trivial cleanups for shmem" from Baolin Wang does as
   it claims.

 - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
   Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.

 - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
   preparatoty refactoring and cleanup of the mremap() code.

 - The series "mm: MM owner tracking for large folios (!hugetlb) +
   CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.

 - The series "mm/damon: add sysfs dirs for managing DAMOS filters based
   on handling layers" from SeongJae Park adds a couple of new sysfs
   directories to ease the management of DAMON/DAMOS filters.

 - The series "arch, mm: reduce code duplication in mem_init()" from
   Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.

 - The series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.

 - The series "mm: page_ext: Introduce new iteration API" from Luiz
   Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.

 - The series "Buddy allocator like (or non-uniform) folio split" from
   Zi Yan reworks the code to split a folio into smaller folios. The
   main benefit is lessened memory consumption: fewer post-split folios
   are generated.

 - The series "Minimize xa_node allocation during xarry split" from Zi
   Yan reduces the number of xarray xa_nodes which are generated during
   an xarray split.

 - The series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.

 - The series "Add tracepoints for lowmem reserves, watermarks and
   totalreserve_pages" from Martin Liu adds some more tracepoints to the
   page allocator code.

 - The series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which
   SeongJae observed during his earlier madvise work.

 - The series "mm/hwpoison: Fix regressions in memory failure handling"
   from Shuai Xue addresses two quite serious regressions which Shuai
   has observed in the memory-failure implementation.

 - The series "mm: reliable huge page allocator" from Johannes Weiner
   makes huge page allocations cheaper and more reliable by reducing
   fragmentation.

 - The series "Minor memcg cleanups &amp; prep for memdescs" from Matthew
   Wilcox is preparatory work for the future implementation of memdescs.

 - The series "track memory used by balloon drivers" from Nico Pache
   introduces a way to track memory used by our various balloon drivers.

 - The series "mm/damon: introduce DAMOS filter type for active pages"
   from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.

 - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
   separates the proactive reclaim statistics from the direct reclaim
   statistics.

 - The series "mm/vmscan: don't try to reclaim hwpoison folio" from
   Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
   code.

* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
  mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
  x86/mm: restore early initialization of high_memory for 32-bits
  mm/vmscan: don't try to reclaim hwpoison folio
  mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
  cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
  mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
  selftests/mm: speed up split_huge_page_test
  selftests/mm: uffd-unit-tests support for hugepages &gt; 2M
  docs/mm/damon/design: document active DAMOS filter type
  mm/damon: implement a new DAMOS filter type for active pages
  fs/dax: don't disassociate zero page entries
  MM documentation: add "Unaccepted" meminfo entry
  selftests/mm: add commentary about 9pfs bugs
  fork: use __vmalloc_node() for stack allocation
  docs/mm: Physical Memory: Populate the "Zones" section
  xen: balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  balloon_compaction: update the NR_BALLOON_PAGES state
  meminfo: add a per node counter for balloon drivers
  mm: remove references to folio in __memcg_kmem_uncharge_page()
  ...
</content>
</entry>
<entry>
<title>perf/core: Fix child_total_time_enabled accounting bug at task exit</title>
<updated>2025-03-31T10:57:38Z</updated>
<author>
<name>Yeoreum Yun</name>
<email>yeoreum.yun@arm.com</email>
</author>
<published>2025-03-26T08:20:03Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=a3c3c66670cee11eb13aa43905904bf29cb92d32'/>
<id>urn:sha1:a3c3c66670cee11eb13aa43905904bf29cb92d32</id>
<content type='text'>
The perf events code fails to account for total_time_enabled of
inactive events.

Here is a failure case for accounting total_time_enabled for
CPU PMU events:

  sudo ./perf stat -vvv -e armv8_pmuv3_0/event=0x08/ -e armv8_pmuv3_1/event=0x08/ -- stress-ng --pthread=2 -t 2s
  ...

  armv8_pmuv3_0/event=0x08/: 1138698008 2289429840 2174835740
  armv8_pmuv3_1/event=0x08/: 1826791390 1950025700 847648440
                             `          `          `
                             `          `          &gt; total_time_running with child
                             `          &gt; total_time_enabled with child
                             &gt; count with child

  Performance counter stats for 'stress-ng --pthread=2 -t 2s':

       1,138,698,008      armv8_pmuv3_0/event=0x08/                                               (94.99%)
       1,826,791,390      armv8_pmuv3_1/event=0x08/                                               (43.47%)

The two events above are opened on two different CPU PMUs, for example,
each event is opened for a cluster in an Arm big.LITTLE system, they
will never run on the same CPU.  In theory, the total enabled time should
be same for both events, as two events are opened and closed together.

As the result show, the two events' total enabled time including
child event is different (2289429840 vs 1950025700).

This is because child events are not accounted properly
if a event is INACTIVE state when the task exits:

  perf_event_exit_event()
   `&gt; perf_remove_from_context()
     `&gt; __perf_remove_from_context()
       `&gt; perf_child_detach()   -&gt; Accumulate child_total_time_enabled
         `&gt; list_del_event()    -&gt; Update child event's time

The problem is the time accumulation happens prior to child event's
time updating. Thus, it misses to account the last period's time when
the event exits.

The perf core layer follows the rule that timekeeping is tied to state
change. To address the issue, make __perf_remove_from_context()
handle the task exit case by passing 'DETACH_EXIT' to it and
invoke perf_event_state() for state alongside with accounting the time.

Then, perf_child_detach() populates the time into the parent's time metrics.

After this patch, the bug is fixed:

  sudo ./perf stat -vvv -e armv8_pmuv3_0/event=0x08/ -e armv8_pmuv3_1/event=0x08/ -- stress-ng --pthread=2 -t 10s
  ...
  armv8_pmuv3_0/event=0x08/: 15396770398 32157963940 21898169000
  armv8_pmuv3_1/event=0x08/: 22428964974 32157963940 10259794940

   Performance counter stats for 'stress-ng --pthread=2 -t 10s':

      15,396,770,398      armv8_pmuv3_0/event=0x08/                                               (68.10%)
      22,428,964,974      armv8_pmuv3_1/event=0x08/                                               (31.90%)

[ mingo: Clarified the changelog. ]

Fixes: ef54c1a476aef ("perf: Rework perf_event_exit_event()")
Suggested-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Yeoreum Yun &lt;yeoreum.yun@arm.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Tested-by: Leo Yan &lt;leo.yan@arm.com&gt;
Link: https://lore.kernel.org/r/20250326082003.1630986-1-yeoreum.yun@arm.com
</content>
</entry>
<entry>
<title>Merge tag 'lsm-pr-20250323' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm</title>
<updated>2025-03-25T22:44:19Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-03-25T22:44:19Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=054570267d232f51b5b234a5354f301f65374dd4'/>
<id>urn:sha1:054570267d232f51b5b234a5354f301f65374dd4</id>
<content type='text'>
Pull lsm updates from Paul Moore:

 - Various minor updates to the LSM Rust bindings

   Changes include marking trivial Rust bindings as inlines and comment
   tweaks to better reflect the LSM hooks.

 - Add LSM/SELinux access controls to io_uring_allowed()

   Similar to the io_uring_disabled sysctl, add a LSM hook to
   io_uring_allowed() to enable LSMs a simple way to enforce security
   policy on the use of io_uring. This pull request includes SELinux
   support for this new control using the io_uring/allowed permission.

 - Remove an unused parameter from the security_perf_event_open() hook

   The perf_event_attr struct parameter was not used by any currently
   supported LSMs, remove it from the hook.

 - Add an explicit MAINTAINERS entry for the credentials code

   We've seen problems in the past where patches to the credentials code
   sent by non-maintainers would often languish on the lists for
   multiple months as there was no one explicitly tasked with the
   responsibility of reviewing and/or merging credentials related code.

   Considering that most of the code under security/ has a vested
   interest in ensuring that the credentials code is well maintained,
   I'm volunteering to look after the credentials code and Serge Hallyn
   has also volunteered to step up as an official reviewer. I posted the
   MAINTAINERS update as a RFC to LKML in hopes that someone else would
   jump up with an "I'll do it!", but beyond Serge it was all crickets.

 - Update Stephen Smalley's old email address to prevent confusion

   This includes a corresponding update to the mailmap file.

* tag 'lsm-pr-20250323' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  mailmap: map Stephen Smalley's old email addresses
  lsm: remove old email address for Stephen Smalley
  MAINTAINERS: add Serge Hallyn as a credentials reviewer
  MAINTAINERS: add an explicit credentials entry
  cred,rust: mark Credential methods inline
  lsm,rust: reword "destroy" -&gt; "release" in SecurityCtx
  lsm,rust: mark SecurityCtx methods inline
  perf: Remove unnecessary parameter of security check
  lsm: fix a missing security_uring_allowed() prototype
  io_uring,lsm,selinux: add LSM hooks for io_uring_setup()
  io_uring: refactor io_uring_allowed()
</content>
</entry>
<entry>
<title>Merge tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2025-03-25T17:54:15Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-03-25T17:54:15Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=a50b4fe095fb98e0b7da03b0a42fd1247284868e'/>
<id>urn:sha1:a50b4fe095fb98e0b7da03b0a42fd1247284868e</id>
<content type='text'>
Pull timer cleanups from Thomas Gleixner:
 "A treewide hrtimer timer cleanup

  hrtimers are initialized with hrtimer_init() and a subsequent store to
  the callback pointer. This turned out to be suboptimal for the
  upcoming Rust integration and is obviously a silly implementation to
  begin with.

  This cleanup replaces the hrtimer_init(T); T-&gt;function = cb; sequence
  with hrtimer_setup(T, cb);

  The conversion was done with Coccinelle and a few manual fixups.

  Once the conversion has completely landed in mainline, hrtimer_init()
  will be removed and the hrtimer::function becomes a private member"

* tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (100 commits)
  wifi: rt2x00: Switch to use hrtimer_update_function()
  io_uring: Use helper function hrtimer_update_function()
  serial: xilinx_uartps: Use helper function hrtimer_update_function()
  ASoC: fsl: imx-pcm-fiq: Switch to use hrtimer_setup()
  RDMA: Switch to use hrtimer_setup()
  virtio: mem: Switch to use hrtimer_setup()
  drm/vmwgfx: Switch to use hrtimer_setup()
  drm/xe/oa: Switch to use hrtimer_setup()
  drm/vkms: Switch to use hrtimer_setup()
  drm/msm: Switch to use hrtimer_setup()
  drm/i915/request: Switch to use hrtimer_setup()
  drm/i915/uncore: Switch to use hrtimer_setup()
  drm/i915/pmu: Switch to use hrtimer_setup()
  drm/i915/perf: Switch to use hrtimer_setup()
  drm/i915/gvt: Switch to use hrtimer_setup()
  drm/i915/huc: Switch to use hrtimer_setup()
  drm/amdgpu: Switch to use hrtimer_setup()
  stm class: heartbeat: Switch to use hrtimer_setup()
  i2c: Switch to use hrtimer_setup()
  iio: Switch to use hrtimer_setup()
  ...
</content>
</entry>
</feed>
