<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/tools/testing/vma, branch v6.18.37</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.18.37</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.18.37'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-06-27T10:06:49+00:00</updated>
<entry>
<title>mm: propagate VM_SOFTDIRTY on merge</title>
<updated>2026-06-27T10:06:49+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2026-05-15T12:42:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=f563ce913a8315bd722c1540a8743a0d12d95d4d'/>
<id>urn:sha1:f563ce913a8315bd722c1540a8743a0d12d95d4d</id>
<content type='text'>
commit 6707915e030a3258868355f989b80140c1a45bbe upstream.

Patch series "make VM_SOFTDIRTY a sticky VMA flag", v2.

Currently we set VM_SOFTDIRTY when a new mapping is set up (whether by
establishing a new VMA, or via merge) as implemented in __mmap_complete()
and do_brk_flags().

However, when performing a merge of existing mappings such as when
performing mprotect(), we may lose the VM_SOFTDIRTY flag.

Now we have the concept of making VMA flags 'sticky', that is that they
both don't prevent merge and, importantly, are propagated to merged VMAs,
this seems a sensible alternative to the existing special-casing of
VM_SOFTDIRTY.

We additionally add a self-test that demonstrates that this logic behaves
as expected.

This patch (of 2):

Currently we set VM_SOFTDIRTY when a new mapping is set up (whether by
establishing a new VMA, or via merge) as implemented in __mmap_complete()
and do_brk_flags().

However, when performing a merge of existing mappings such as when
performing mprotect(), we may lose the VM_SOFTDIRTY flag.

This is because currently we simply ignore VM_SOFTDIRTY for the purposes
of merge, so one VMA may possess the flag and another not, and whichever
happens to be the target VMA will be the one upon which the merge is
performed which may or may not have VM_SOFTDIRTY set.

Now we have the concept of 'sticky' VMA flags, let's make VM_SOFTDIRTY one
which solves this issue.

Additionally update VMA userland tests to propagate changes.

[akpm@linux-foundation.org: update comments, per Lorenzo]
  Link: https://lkml.kernel.org/r/0019e0b8-ee1e-4359-b5ee-94225cbe5588@lucifer.local
Link: https://lkml.kernel.org/r/cover.1763399675.git.ljs@kernel.org
Link: https://lkml.kernel.org/r/955478b5170715c895d1ef3b7f68e0cd77f76868.1763399675.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Suggested-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: David Hildenbrand (Red Hat) &lt;david@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Acked-by: Andrey Vagin &lt;avagin@gmail.com&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Cyrill Gorcunov &lt;gorcunov@gmail.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Ahmed Elaidy &lt;elaidya225@gmail.com&gt;
Fixes: 34228d473efe ("mm: ignore VM_SOFTDIRTY on VMA merging")
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: introduce copy-on-fork VMAs and make VM_MAYBE_GUARD one</title>
<updated>2026-06-27T10:06:49+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2026-05-15T12:42:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3d6cb2ed06f7f3c7b3d05a7d77e4b2c4a3dd930b'/>
<id>urn:sha1:3d6cb2ed06f7f3c7b3d05a7d77e4b2c4a3dd930b</id>
<content type='text'>
commit ab04b530e7e8bd5cf9fb0c1ad20e0deee8f569ec upstream.

Gather all the VMA flags whose presence implies that page tables must be
copied on fork into a single bitmap - VM_COPY_ON_FORK - and use this
rather than specifying individual flags in vma_needs_copy().

We also add VM_MAYBE_GUARD to this list, as it being set on a VMA implies
that there may be metadata contained in the page tables (that is - guard
markers) which would will not and cannot be propagated upon fork.

This was already being done manually previously in vma_needs_copy(), but
this makes it very explicit, alongside VM_PFNMAP, VM_MIXEDMAP and
VM_UFFD_WP all of which imply the same.

Note that VM_STICKY flags ought generally to be marked VM_COPY_ON_FORK too
- because equally a flag being VM_STICKY indicates that the VMA contains
metadat that is not propagated by being faulted in - i.e.  that the VMA
metadata does not fully describe the VMA alone, and thus we must propagate
whatever metadata there is on a fork.

However, for maximum flexibility, we do not make this necessarily the case
here.

Link: https://lkml.kernel.org/r/5d41b24e7bc622cda0af92b6d558d7f4c0d1bc8c.1763460113.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: David Hildenbrand (Red Hat) &lt;david@kernel.org&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: Dev Jain &lt;dev.jain@arm.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Lance Yang &lt;lance.yang@linux.dev&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: "Masami Hiramatsu (Google)" &lt;mhiramat@kernel.org&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Nico Pache &lt;npache@redhat.com&gt;
Cc: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Ahmed Elaidy &lt;elaidya225@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: implement sticky VMA flags</title>
<updated>2026-06-27T10:06:49+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2026-05-15T12:42:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=05cdec24a858967c7dc768f6b66a71f61f5ed1ee'/>
<id>urn:sha1:05cdec24a858967c7dc768f6b66a71f61f5ed1ee</id>
<content type='text'>
commit 64212ba02e66e705cabce188453ba4e61e9d7325 upstream.

It is useful to be able to designate that certain flags are 'sticky', that
is, if two VMAs are merged one with a flag of this nature and one without,
the merged VMA sets this flag.

As a result we ignore these flags for the purposes of determining VMA flag
differences between VMAs being considered for merge.

This patch therefore updates the VMA merge logic to perform this action,
with flags possessing this property being described in the VM_STICKY
bitmap.

Those flags which ought to be ignored for the purposes of VMA merge are
described in the VM_IGNORE_MERGE bitmap, which the VMA merge logic is also
updated to use.

As part of this change we place VM_SOFTDIRTY in VM_IGNORE_MERGE as it
already had this behaviour, alongside VM_STICKY as sticky flags by
implication must not disallow merge.

Ultimately it seems that we should make VM_SOFTDIRTY a sticky flag in its
own right, but this change is out of scope for this series.

The only sticky flag designated as such is VM_MAYBE_GUARD, so as a result
of this change, once the VMA flag is set upon guard region installation,
VMAs with guard ranges will now not have their merge behaviour impacted as
a result and can be freely merged with other VMAs without VM_MAYBE_GUARD
set.

Also update the comments for vma_modify_flags() to directly reference
sticky flags now we have established the concept.

We also update the VMA userland tests to account for the changes.

Link: https://lkml.kernel.org/r/22ad5269f7669d62afb42ce0c79bad70b994c58d.1763460113.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: David Hildenbrand (Red Hat) &lt;david@kernel.org&gt;
Cc: Dev Jain &lt;dev.jain@arm.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Lance Yang &lt;lance.yang@linux.dev&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: "Masami Hiramatsu (Google)" &lt;mhiramat@kernel.org&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Nico Pache &lt;npache@redhat.com&gt;
Cc: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Ahmed Elaidy &lt;elaidya225@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: update vma_modify_flags() to handle residual flags, document</title>
<updated>2026-06-27T10:06:49+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2026-05-15T12:42:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a093c80a1f139425c7cf186b91e5ed5c7b27d98e'/>
<id>urn:sha1:a093c80a1f139425c7cf186b91e5ed5c7b27d98e</id>
<content type='text'>
commit 9119d6c2095bb20292cb9812dd70d37f17e3bd37 upstream.

The vma_modify_*() family of functions each either perform splits, a merge
or no changes at all in preparation for the requested modification to
occur.

When doing so for a VMA flags change, we currently don't account for any
flags which may remain (for instance, VM_SOFTDIRTY) despite the requested
change in the case that a merge succeeded.

This is made more important by subsequent patches which will introduce the
concept of sticky VMA flags which rely on this behaviour.

This patch fixes this by passing the VMA flags parameter as a pointer and
updating it accordingly on merge and updating callers to accommodate for
this.

Additionally, while we are here, we add kdocs for each of the
vma_modify_*() functions, as the fact that the requested modification is
not performed is confusing so it is useful to make this abundantly clear.

We also update the VMA userland tests to account for this change.

Link: https://lkml.kernel.org/r/23b5b549b0eaefb2922625626e58c2a352f3e93c.1763460113.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: David Hildenbrand (Red Hat) &lt;david@kernel.org&gt;
Cc: Dev Jain &lt;dev.jain@arm.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Lance Yang &lt;lance.yang@linux.dev&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: "Masami Hiramatsu (Google)" &lt;mhiramat@kernel.org&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Nico Pache &lt;npache@redhat.com&gt;
Cc: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Ahmed Elaidy &lt;elaidya225@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: introduce VM_MAYBE_GUARD and make visible in /proc/$pid/smaps</title>
<updated>2026-06-27T10:06:48+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2026-05-15T12:42:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=efce8a486bffcbad9897b059f05a01b8f25197ea'/>
<id>urn:sha1:efce8a486bffcbad9897b059f05a01b8f25197ea</id>
<content type='text'>
commit 5dba5cc2e0ffa76f2f6c8922a04469dc9602c396 upstream.

Patch series "introduce VM_MAYBE_GUARD and make it sticky", v4.

Currently, guard regions are not visible to users except through
/proc/$pid/pagemap, with no explicit visibility at the VMA level.

This makes the feature less useful, as it isn't entirely apparent which
VMAs may have these entries present, especially when performing actions
which walk through memory regions such as those performed by CRIU.

This series addresses this issue by introducing the VM_MAYBE_GUARD flag
which fulfils this role, updating the smaps logic to display an entry for
these.

The semantics of this flag are that a guard region MAY be present if set
(we cannot be sure, as we can't efficiently track whether an
MADV_GUARD_REMOVE finally removes all the guard regions in a VMA) - but if
not set the VMA definitely does NOT have any guard regions present.

It's problematic to establish this flag without further action, because
that means that VMAs with guard regions in them become non-mergeable with
adjacent VMAs for no especially good reason.

To work around this, this series also introduces the concept of 'sticky'
VMA flags - that is flags which:

a. if set in one VMA and not in another still permit those VMAs to be
   merged (if otherwise compatible).

b. When they are merged, the resultant VMA must have the flag set.

The VMA logic is updated to propagate these flags correctly.

Additionally, VM_MAYBE_GUARD being an explicit VMA flag allows us to solve
an issue with file-backed guard regions - previously these established an
anon_vma object for file-backed mappings solely to have vma_needs_copy()
correctly propagate guard region mappings to child processes.

We introduce a new flag alias VM_COPY_ON_FORK (which currently only
specifies VM_MAYBE_GUARD) and update vma_needs_copy() to check explicitly
for this flag and to copy page tables if it is present, which resolves
this issue.

Additionally, we add the ability for allow-listed VMA flags to be
atomically writable with only mmap/VMA read locks held.

The only flag we allow so far is VM_MAYBE_GUARD, which we carefully ensure
does not cause any races by being allowed to do so.

This allows us to maintain guard region installation as a read-locked
operation and not endure the overhead of obtaining a write lock here.

Finally we introduce extensive VMA userland tests to assert that the
sticky VMA logic behaves correctly as well as guard region self tests to
assert that smaps visibility is correctly implemented.

This patch (of 9):

Currently, if a user needs to determine if guard regions are present in a
range, they have to scan all VMAs (or have knowledge of which ones might
have guard regions).

Since commit 8e2f2aeb8b48 ("fs/proc/task_mmu: add guard region bit to
pagemap") and the related commit a516403787e0 ("fs/proc: extend the
PAGEMAP_SCAN ioctl to report guard regions"), users can use either
/proc/$pid/pagemap or the PAGEMAP_SCAN functionality to perform this
operation at a virtual address level.

This is not ideal, and it gives no visibility at a /proc/$pid/smaps level
that guard regions exist in ranges.

This patch remedies the situation by establishing a new VMA flag,
VM_MAYBE_GUARD, to indicate that a VMA may contain guard regions (it is
uncertain because we cannot reasonably determine whether a
MADV_GUARD_REMOVE call has removed all of the guard regions in a VMA, and
additionally VMAs may change across merge/split).

We utilise 0x800 for this flag which makes it available to 32-bit
architectures also, a flag that was previously used by VM_DENYWRITE, which
was removed in commit 8d0920bde5eb ("mm: remove VM_DENYWRITE") and hasn't
bee reused yet.

We also update the smaps logic and documentation to identify these VMAs.

Another major use of this functionality is that we can use it to identify
that we ought to copy page tables on fork.

We do not actually implement usage of this flag in mm/madvise.c yet as we
need to allow some VMA flags to be applied atomically under mmap/VMA read
lock in order to avoid the need to acquire a write lock for this purpose.

Link: https://lkml.kernel.org/r/cover.1763460113.git.ljs@kernel.org
Link: https://lkml.kernel.org/r/cf8ef821eba29b6c5b5e138fffe95d6dcabdedb9.1763460113.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: David Hildenbrand (Red Hat) &lt;david@kernel.org&gt;
Reviewed-by: Lance Yang &lt;lance.yang@linux.dev&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: Dev Jain &lt;dev.jain@arm.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: "Masami Hiramatsu (Google)" &lt;mhiramat@kernel.org&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Nico Pache &lt;npache@redhat.com&gt;
Cc: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Ahmed Elaidy &lt;elaidya225@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: prevent droppable mappings from being locked</title>
<updated>2026-05-07T04:11:59+00:00</updated>
<author>
<name>Anthony Yznaga</name>
<email>anthony.yznaga@oracle.com</email>
</author>
<published>2026-04-28T20:05:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=6f977b0472f700e4bcb981342ceacf2f1b1a3671'/>
<id>urn:sha1:6f977b0472f700e4bcb981342ceacf2f1b1a3671</id>
<content type='text'>
[ Upstream commit d239462787b072c78eb19fc1f155c3d411256282 ]

Droppable mappings must not be lockable.  There is a check for VMAs with
VM_DROPPABLE set in mlock_fixup() along with checks for other types of
unlockable VMAs which ensures this when calling mlock()/mlock2().

For mlockall(MCL_FUTURE), the check for unlockable VMAs is different.  In
apply_mlockall_flags(), if the flags parameter has MCL_FUTURE set, the
current task's mm's default VMA flag field mm-&gt;def_flags has VM_LOCKED
applied to it.  VM_LOCKONFAULT is also applied if MCL_ONFAULT is also set.
When these flags are set as default in this manner they are cleared in
__mmap_complete() for new mappings that do not support mlock.  A check for
VM_DROPPABLE in __mmap_complete() is missing resulting in droppable
mappings created with VM_LOCKED set.  To fix this and reduce that chance
of similar bugs in the future, introduce and use vma_supports_mlock().

Link: https://lkml.kernel.org/r/20260310155821.17869-1-anthony.yznaga@oracle.com
Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings")
Signed-off-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Suggested-by: David Hildenbrand &lt;david@kernel.org&gt;
Acked-by: David Hildenbrand (Arm) &lt;david@kernel.org&gt;
Reviewed-by: Pedro Falcato &lt;pfalcato@suse.de&gt;
Reviewed-by: Lorenzo Stoakes (Oracle) &lt;ljs@kernel.org&gt;
Tested-by: Lorenzo Stoakes (Oracle) &lt;ljs@kernel.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jason A. Donenfeld &lt;jason@zx2c4.com&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vlastimil Babka &lt;vbabka@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
[ added const to is_vm_hugetlb_page and stubbed vma_supports_mlock in vma_internal.h instead of the split-out stubs.h ]
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2025-10-03T01:18:33+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-10-03T01:18:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8804d970fab45726b3c7cd7f240b31122aa94219'/>
<id>urn:sha1:8804d970fab45726b3c7cd7f240b31122aa94219</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - "mm, swap: improve cluster scan strategy" from Kairui Song improves
   performance and reduces the failure rate of swap cluster allocation

 - "support large align and nid in Rust allocators" from Vitaly Wool
   permits Rust allocators to set NUMA node and large alignment when
   perforning slub and vmalloc reallocs

 - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend
   DAMOS_STAT's handling of the DAMON operations sets for virtual
   address spaces for ops-level DAMOS filters

 - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren
   Baghdasaryan reduces mmap_lock contention during reads of
   /proc/pid/maps

 - "mm/mincore: minor clean up for swap cache checking" from Kairui Song
   performs some cleanup in the swap code

 - "mm: vm_normal_page*() improvements" from David Hildenbrand provides
   code cleanup in the pagemap code

 - "add persistent huge zero folio support" from Pankaj Raghav provides
   a block layer speedup by optionalls making the
   huge_zero_pagepersistent, instead of releasing it when its refcount
   falls to zero

 - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to
   the recently added Kexec Handover feature

 - "mm: make mm-&gt;flags a bitmap and 64-bit on all arches" from Lorenzo
   Stoakes turns mm_struct.flags into a bitmap. To end the constant
   struggle with space shortage on 32-bit conflicting with 64-bit's
   needs

 - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap
   code

 - "selftests/mm: Fix false positives and skip unsupported tests" from
   Donet Tom fixes a few things in our selftests code

 - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised"
   from David Hildenbrand "allows individual processes to opt-out of
   THP=always into THP=madvise, without affecting other workloads on the
   system".

   It's a long story - the [1/N] changelog spells out the considerations

 - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on
   the memdesc project. Please see

      https://kernelnewbies.org/MatthewWilcox/Memdescs and
      https://blogs.oracle.com/linux/post/introducing-memdesc

 - "Tiny optimization for large read operations" from Chi Zhiling
   improves the efficiency of the pagecache read path

 - "Better split_huge_page_test result check" from Zi Yan improves our
   folio splitting selftest code

 - "test that rmap behaves as expected" from Wei Yang adds some rmap
   selftests

 - "remove write_cache_pages()" from Christoph Hellwig removes that
   function and converts its two remaining callers

 - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD
   selftests issues

 - "introduce kernel file mapped folios" from Boris Burkov introduces
   the concept of "kernel file pages". Using these permits btrfs to
   account its metadata pages to the root cgroup, rather than to the
   cgroups of random inappropriate tasks

 - "mm/pageblock: improve readability of some pageblock handling" from
   Wei Yang provides some readability improvements to the page allocator
   code

 - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON
   to understand arm32 highmem

 - "tools: testing: Use existing atomic.h for vma/maple tests" from
   Brendan Jackman performs some code cleanups and deduplication under
   tools/testing/

 - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes
   a couple of 32-bit issues in tools/testing/radix-tree.c

 - "kasan: unify kasan_enabled() and remove arch-specific
   implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific
   initialization code into a common arch-neutral implementation

 - "mm: remove zpool" from Johannes Weiner removes zspool - an
   indirection layer which now only redirects to a single thing
   (zsmalloc)

 - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a
   couple of cleanups in the fork code

 - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of
   adjustments at various nth_page() callsites, eventually permitting
   the removal of that undesirable helper function

 - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun
   creates a KASAN read-only mode for ARM, using that architecture's
   memory tagging feature. It is felt that a read-only mode KASAN is
   suitable for use in production systems rather than debug-only

 - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does
   some tidying in the hugetlb folio allocation code

 - "mm: establish const-correctness for pointer parameters" from Max
   Kellermann makes quite a number of the MM API functions more accurate
   about the constness of their arguments. This was getting in the way
   of subsystems (in this case CEPH) when they attempt to improving
   their own const/non-const accuracy

 - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of
   code sites which were confused over when to use free_pages() vs
   __free_pages()

 - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the
   mapletree code accessible to Rust. Required by nouveau and by its
   forthcoming successor: the new Rust Nova driver

 - "selftests/mm: split_huge_page_test: split_pte_mapped_thp
   improvements" from David Hildenbrand adds a fix and some cleanups to
   the thp selftesting code

 - "mm, swap: introduce swap table as swap cache (phase I)" from Chris
   Li and Kairui Song is the first step along the path to implementing
   "swap tables" - a new approach to swap allocation and state tracking
   which is expected to yield speed and space improvements. This
   patchset itself yields a 5-20% performance benefit in some situations

 - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc
   layer to clean up the ptdesc code a little

 - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some
   issues in our 5-level pagetable selftesting code

 - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan
   addresses a couple of minor issues in relatively new memory
   allocation profiling feature

 - "Small cleanups" from Matthew Wilcox has a few cleanups in
   preparation for more memdesc work

 - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from
   Quanmin Yan makes some changes to DAMON in furtherance of supporting
   arm highmem

 - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad
   Anjum adds that compiler check to selftests code and fixes the
   fallout, by removing dead code

 - "Improvements to Victim Process Thawing and OOM Reaper Traversal
   Order" from zhongjinji makes a number of improvements in the OOM
   killer: mainly thawing a more appropriate group of victim threads so
   they can release resources

 - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park
   is a bunch of small and unrelated fixups for DAMON

 - "mm/damon: define and use DAMON initialization check function" from
   SeongJae Park implement reliability and maintainability improvements
   to a recently-added bug fix

 - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from
   SeongJae Park provides additional transparency to userspace clients
   of the DAMON_STAT information

 - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes
   some constraints on khubepaged's collapsing of anon VMAs. It also
   increases the success rate of MADV_COLLAPSE against an anon vma

 - "mm: do not assume file == vma-&gt;vm_file in compat_vma_mmap_prepare()"
   from Lorenzo Stoakes moves us further towards removal of
   file_operations.mmap(). This patchset concentrates upon clearing up
   the treatment of stacked filesystems

 - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau
   provides some fixes and improvements to mlock's tracking of large
   folios. /proc/meminfo's "Mlocked" field became more accurate

 - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from
   Donet Tom fixes several user-visible KSM stats inaccuracies across
   forks and adds selftest code to verify these counters

 - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses
   some potential but presently benign issues in KSM's mm_slot handling

* tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits)
  mm: swap: check for stable address space before operating on the VMA
  mm: convert folio_page() back to a macro
  mm/khugepaged: use start_addr/addr for improved readability
  hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list
  alloc_tag: fix boot failure due to NULL pointer dereference
  mm: silence data-race in update_hiwater_rss
  mm/memory-failure: don't select MEMORY_ISOLATION
  mm/khugepaged: remove definition of struct khugepaged_mm_slot
  mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL
  hugetlb: increase number of reserving hugepages via cmdline
  selftests/mm: add fork inheritance test for ksm_merging_pages counter
  mm/ksm: fix incorrect KSM counter handling in mm_struct during fork
  drivers/base/node: fix double free in register_one_node()
  mm: remove PMD alignment constraint in execmem_vmalloc()
  mm/memory_hotplug: fix typo 'esecially' -&gt; 'especially'
  mm/rmap: improve mlock tracking for large folios
  mm/filemap: map entire large folio faultaround
  mm/fault: try to map the entire file folio in finish_fault()
  mm/rmap: mlock large folios in try_to_unmap_one()
  mm/rmap: fix a mlock race condition in folio_referenced_one()
  ...
</content>
</entry>
<entry>
<title>tools/testing: Add support for changes to slab for sheaves</title>
<updated>2025-09-29T07:22:44+00:00</updated>
<author>
<name>Liam R. Howlett</name>
<email>Liam.Howlett@Oracle.com</email>
</author>
<published>2025-09-03T12:59:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c4fb7f0a79771dfd18838bfc5015650a9730e9c0'/>
<id>urn:sha1:c4fb7f0a79771dfd18838bfc5015650a9730e9c0</id>
<content type='text'>
The slab changes for sheaves requires more effort in the testing code.
Unite all the kmem_cache work into the tools/include slab header for
both the vma and maple tree testing.

The vma test code also requires importing more #defines to allow for
seamless use of the shared kmem_cache code.

This adds the pthread header to the slab header in the tools directory
to allow for the pthread_mutex in linux.c.

Signed-off-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Reviewed-by: Suren Baghdasaryan &lt;surenb@google.com&gt;
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
</content>
</entry>
<entry>
<title>tools/testing/vma: Implement vm_refcnt reset</title>
<updated>2025-09-29T07:21:16+00:00</updated>
<author>
<name>Liam R. Howlett</name>
<email>Liam.Howlett@oracle.com</email>
</author>
<published>2025-09-03T12:59:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=d09a61a3aa7de53fe055743993d79eaeb945cbad'/>
<id>urn:sha1:d09a61a3aa7de53fe055743993d79eaeb945cbad</id>
<content type='text'>
Add the reset of the ref count in vma_lock_init().  This is needed if
the vma memory is not zeroed on allocation.

Signed-off-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Reviewed-by: Suren Baghdasaryan &lt;surenb@google.com&gt;
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
</content>
</entry>
<entry>
<title>tools/testing/vma: clean up stubs in vma_internal.h</title>
<updated>2025-09-29T07:21:16+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2025-08-26T10:28:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=da577f1fcbdd0317b7c5089c19d5d61ec194f0e0'/>
<id>urn:sha1:da577f1fcbdd0317b7c5089c19d5d61ec194f0e0</id>
<content type='text'>
We do not need to references arguments just to avoid compiler warnings,
the warning in question does not arise here, so remove all of the
instances of '(void)xxx' introduced purely to avoid this warning.

As reported by WagYuli in the referenced mail, GCC 8.3 and before will
have issues compiling this file if parameter names are not provided, so
ensure these are always provided.

Finally, perform a trivial fix up of kmem_cache_alloc() which technically
has parameters in the incorrect order (as reported by Vlastimil Babka
off-list).

Link: https://lkml.kernel.org/r/20250826102824.22730-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Reported-by: WangYuli &lt;wangyuli@uniontech.com&gt;
Closes: https://lore.kernel.org/linux-mm/EFCEBE7E301589DE+20250729084700.208767-1-wangyuli@uniontech.com/
Reported-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Reviewed-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: WangYuli &lt;wangyuli@uniontech.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
</content>
</entry>
</feed>
