From: Rik van Riel <riel@surriel.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Dmitry Ilvokhin <d@ilvokhin.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>
Subject: Re: [PATCH 3/3] mm: read remote memory without the mmap lock where possible
Date: Fri, 19 Jun 2026 09:46:59 -0400 [thread overview]
Message-ID: <af82cd43ef0c5bd4a5337942650fba3b8bccd94b.camel@surriel.com> (raw)
In-Reply-To: <CAJuCfpHHkQyj7MMoH++RGraZgQ1Hr+4=T4PfbBn-minUCZyuOQ@mail.gmail.com>
On Tue, 2026-06-16 at 23:19 -0700, Suren Baghdasaryan wrote:
>
> I don't think we should be using per-VMA locks if the read spans
> multiple VMAs. Doing that would risk a possibility of reading
> inconsistent data since we are locking one VMA at a time. While we
> load and read VMA, its neighboring VMA can be unmapped and another
> one
> can be mapped in its place.
How is that different from userspace overwriting
data while we are reading it, and us reading half
new, and half old contents?
We already have nothing synchronizing the contents
today.
All our locking does is protect the metadata we
use to find the memory.
--
All Rights Reversed.
next prev parent reply other threads:[~2026-06-19 13:47 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-16 19:02 [PATCH 0/3] mm: __access_remote_vm with per-VMA lock Rik van Riel
2026-06-16 19:02 ` [PATCH 1/3] x86/mm: use READ_ONCE/WRITE_ONCE for mm->context.untag_mask Rik van Riel
2026-06-18 16:40 ` Usama Arif
2026-06-16 19:02 ` [PATCH 2/3] mm/pagewalk: let folio_walk_start() run under the per-VMA lock Rik van Riel
2026-06-19 12:34 ` Lorenzo Stoakes
2026-06-16 19:03 ` [PATCH 3/3] mm: read remote memory without the mmap lock where possible Rik van Riel
2026-06-17 6:19 ` Suren Baghdasaryan
2026-06-19 12:24 ` Lorenzo Stoakes
2026-06-19 13:46 ` Rik van Riel [this message]
2026-06-19 14:03 ` Suren Baghdasaryan
2026-06-19 14:33 ` David Hildenbrand (Arm)
2026-06-18 17:01 ` Usama Arif
2026-06-18 17:07 ` David Hildenbrand (Arm)
2026-06-18 17:22 ` Usama Arif
2026-06-19 12:20 ` Lorenzo Stoakes
2026-06-17 1:10 ` [PATCH 0/3] mm: __access_remote_vm with per-VMA lock Suren Baghdasaryan
2026-06-17 9:42 ` David Hildenbrand (Arm)
2026-06-17 13:33 ` Suren Baghdasaryan
2026-06-18 20:37 ` David Hildenbrand (Arm)
2026-06-19 12:43 ` Lorenzo Stoakes
2026-06-19 13:04 ` David Hildenbrand (Arm)
2026-06-19 14:19 ` Suren Baghdasaryan
2026-06-19 14:27 ` David Hildenbrand (Arm)
2026-06-19 15:07 ` Suren Baghdasaryan
2026-06-25 1:50 [PATCH v2 " Rik van Riel
2026-06-25 1:50 ` [PATCH 3/3] mm: read remote memory without the mmap lock where possible Rik van Riel
2026-06-25 7:39 ` Lorenzo Stoakes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=af82cd43ef0c5bd4a5337942650fba3b8bccd94b.camel@surriel.com \
--to=riel@surriel.com \
--cc=akpm@linux-foundation.org \
--cc=bp@alien8.de \
--cc=d@ilvokhin.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@kernel.org \
--cc=liam@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=mingo@redhat.com \
--cc=surenb@google.com \
--cc=tglx@kernel.org \
--cc=vbabka@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome