From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Pedro Falcato <pfalcato@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
David Hildenbrand <david@redhat.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Mike Rapoport <rppt@kernel.org>, Michal Hocko <mhocko@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Jann Horn <jannh@google.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-doc@vger.kernel.org, linux-mm@kvack.org,
linux-trace-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org, Andrei Vagin <avagin@gmail.com>,
Barry Song <21cnbao@gmail.com>
Subject: Re: [PATCH 1/3] mm: introduce VM_MAYBE_GUARD and make visible for guard regions
Date: Mon, 3 Nov 2025 09:34:31 +0000 [thread overview]
Message-ID: <15d3b854-a2f2-42a3-b2ab-3a8c822dae9f@lucifer.local> (raw)
In-Reply-To: <CAJuCfpEs1JTywfZNPrVmeTHUUyK+7waCU9fqfur2Q_xxx7hacw@mail.gmail.com>
On Fri, Oct 31, 2025 at 04:12:51PM -0700, Suren Baghdasaryan wrote:
>
> Overall, I think it should be possible to set this flag atomically
> under VMA read-lock. However, if you introduce new vm_flags
> manipulation functions, please make sure they can't be used for other
> vm_flags. In Android I've seen several "interesting" attempts to
> update vm_flags under a read-lock (specifically in the page-fault
> path) and had to explain why that's a bad idea.
Yeah agreed, so the idea would be to absolutely ring-fence any flag we do
this with entirely. Probably a VM_WARN_ON_ONCE() for anybody trying it with
other flags so bots can catch anybody being naughty.
That kind of 'interesting' stuff is another reason I prefer to really limit
what drivers can do btw ;)
Will have a respin with this idea applied relatively soon hopefully.
Cheers, Lorenzo
next prev parent reply other threads:[~2025-11-03 9:43 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 16:50 [PATCH 0/3] introduce VM_MAYBE_GUARD and make it sticky Lorenzo Stoakes
2025-10-29 16:50 ` [PATCH 1/3] mm: introduce VM_MAYBE_GUARD and make visible for guard regions Lorenzo Stoakes
2025-10-29 19:50 ` Randy Dunlap
2025-10-30 8:13 ` Lorenzo Stoakes
2025-10-30 1:05 ` Suren Baghdasaryan
2025-10-30 8:22 ` Lorenzo Stoakes
2025-10-30 16:16 ` Pedro Falcato
2025-10-30 16:23 ` Lorenzo Stoakes
2025-10-30 16:31 ` Pedro Falcato
2025-10-30 16:43 ` Lorenzo Stoakes
2025-10-30 18:31 ` Vlastimil Babka
2025-10-30 18:47 ` Vlastimil Babka
2025-10-30 19:47 ` Lorenzo Stoakes
2025-10-30 21:48 ` Vlastimil Babka
2025-10-31 23:12 ` Suren Baghdasaryan
2025-11-03 9:34 ` Lorenzo Stoakes [this message]
2025-11-05 19:48 ` Lorenzo Stoakes
2025-11-06 7:34 ` Vlastimil Babka
2025-10-30 19:16 ` Lorenzo Stoakes
2025-10-30 19:37 ` Lorenzo Stoakes
2025-10-29 16:50 ` [PATCH 2/3] mm: implement sticky, copy on fork VMA flags Lorenzo Stoakes
2025-10-30 4:35 ` Suren Baghdasaryan
2025-10-30 8:25 ` Lorenzo Stoakes
2025-10-30 16:25 ` Pedro Falcato
2025-10-30 16:34 ` Lorenzo Stoakes
2025-10-29 16:50 ` [PATCH 3/3] selftests/mm/guard-regions: add smaps visibility test Lorenzo Stoakes
2025-10-30 4:40 ` Suren Baghdasaryan
2025-10-30 8:25 ` Lorenzo Stoakes
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