linux-kernel - Re: [PATCH v3 3/8] mm: implement sticky VMA flags

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251117144332.d338e8368d59c3ab665db986@linux-foundation.org>
Date: Mon, 17 Nov 2025 14:43:32 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: Jonathan Corbet <corbet@....net>, David Hildenbrand <david@...hat.com>,
 "Liam R . Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka
 <vbabka@...e.cz>, Mike Rapoport <rppt@...nel.org>, Suren Baghdasaryan
 <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>, Steven Rostedt
 <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>, Mathieu
 Desnoyers <mathieu.desnoyers@...icios.com>, Jann Horn <jannh@...gle.com>,
 Pedro Falcato <pfalcato@...e.de>, Zi Yan <ziy@...dia.com>, Baolin Wang
 <baolin.wang@...ux.alibaba.com>, Nico Pache <npache@...hat.com>, Ryan
 Roberts <ryan.roberts@....com>, Dev Jain <dev.jain@....com>, Barry Song
 <baohua@...nel.org>, Lance Yang <lance.yang@...ux.dev>,
 linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
 linux-doc@...r.kernel.org, linux-mm@...ck.org,
 linux-trace-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org, Andrei
 Vagin <avagin@...il.com>
Subject: Re: [PATCH v3 3/8] mm: implement sticky VMA flags

On Mon, 17 Nov 2025 20:02:03 +0000 Lorenzo Stoakes <lorenzo.stoakes@...cle.com> wrote:

> Sorry to be a pain here, and can respin if it's easier, but can we update the
> text of the comments below? As in discussion with Liam off-list we agreed that
> the current wording is rather unclear and we can do a lot better.
> 
> I provide the improved version inline below:

np,

 include/linux/mm.h               |    7 +++----
 tools/testing/vma/vma_internal.h |    7 +++----
 2 files changed, 6 insertions(+), 8 deletions(-)

--- a/include/linux/mm.h~mm-implement-sticky-vma-flags-fix-2
+++ a/include/linux/mm.h
@@ -549,10 +549,9 @@ extern unsigned int kobjsize(const void
  *                pressure on the memory system forcing the kernel to generate
  *                new VMAs when old one could be extended instead.
  *
- *    VM_STICKY - If one VMA has flags which most be 'sticky', that is ones
- *                which should propagate to all VMAs, but the other does not,
- *                the merge should still proceed with the merge logic applying
- *                sticky flags to the final VMA.
+ *    VM_STICKY - When merging VMAs, VMA flags must match, unless they are
+ *                'sticky'. If any sticky flags exist in either VMA, we simply
+ *                set all of them on the merged VMA.
  */
 #define VM_IGNORE_MERGE (VM_SOFTDIRTY | VM_STICKY)

--- a/tools/testing/vma/vma_internal.h~mm-implement-sticky-vma-flags-fix-2
+++ a/tools/testing/vma/vma_internal.h
@@ -139,10 +139,9 @@ extern unsigned long dac_mmap_min_addr;
  *                pressure on the memory system forcing the kernel to generate
  *                new VMAs when old one could be extended instead.
  *
- *    VM_STICKY - If one VMA has flags which most be 'sticky', that is ones
- *                which should propagate to all VMAs, but the other does not,
- *                the merge should still proceed with the merge logic applying
- *                sticky flags to the final VMA.
+ *    VM_STICKY - When merging VMAs, VMA flags must match, unless they are
+ *                'sticky'. If any sticky flags exist in either VMA, we simply
+ *                set all of them on the merged VMA.
  */
 #define VM_IGNORE_MERGE (VM_SOFTDIRTY | VM_STICKY)

_