From: Andrew Morton <akpm@linux-foundation.org>
To: Oskar Gerlicz Kowalczuk <oskar@gerlicz.space>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>,
Mike Rapoport <rppt@kernel.org>, Baoquan He <bhe@redhat.com>,
Pratyush Yadav <pratyush@kernel.org>,
linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
linux-mm@kvack.org
Subject: Re: [PATCH 1/5] liveupdate: block outgoing session updates during reboot
Date: Fri, 20 Mar 2026 18:23:52 -0700 [thread overview]
Message-ID: <20260320182352.ca6c88e409ff12d0368b03ae@linux-foundation.org> (raw)
In-Reply-To: <20260320163720.100456-1-oskar@gerlicz.space>
On Fri, 20 Mar 2026 17:37:16 +0100 Oskar Gerlicz Kowalczuk <oskar@gerlicz.space> wrote:
> When kernel_kexec() starts a live update handover, LUO serializes
> outgoing sessions before the reboot path freezes tasks or shuts
> devices down. That leaves a window where close() and
> LIVEUPDATE_SESSION_PRESERVE_FD can still mutate an existing outgoing
> session after luo_session_serialize() has already captured it.
>
> The race is dangerous because the next kernel may inherit stale file
> metadata or references to memory that userspace has already
> unpreserved. That breaks handover consistency and can later trigger
> restore failures on already torn down state.
>
> Mark the outgoing session set as rebooting while serialization is in
> progress, reject new mutations with -EBUSY, and make release wait
> until rebooting finishes before unpreserving files. Reset the flag and
> wake waiters when serialization rolls back, and use READ_ONCE() and
> WRITE_ONCE() so the state is visible across CPUs.
Sashiko AI review has quite a few questions:
https://sashiko.dev/#/patchset/20260320163720.100456-1-oskar@gerlicz.space
next prev parent reply other threads:[~2026-03-21 1:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-20 16:37 [PATCH 1/5] liveupdate: block outgoing session updates during reboot Oskar Gerlicz Kowalczuk
2026-03-20 16:37 ` [PATCH 2/5] kexec: abort liveupdate handover on kernel_kexec() unwind Oskar Gerlicz Kowalczuk
2026-03-20 16:37 ` [PATCH 3/5] liveupdate: fail session restore on file deserialization errors Oskar Gerlicz Kowalczuk
2026-03-20 16:37 ` [PATCH 4/5] liveupdate: validate handover metadata before using it Oskar Gerlicz Kowalczuk
2026-03-20 16:37 ` [PATCH 5/5] liveupdate: guard FLB counters against underflow Oskar Gerlicz Kowalczuk
2026-03-21 1:23 ` Andrew Morton [this message]
2026-03-21 10:25 ` [PATCH 1/5] liveupdate: block outgoing session updates during reboot oskar
2026-03-22 7:40 ` kernel test robot
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=20260320182352.ca6c88e409ff12d0368b03ae@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=oskar@gerlicz.space \
--cc=pasha.tatashin@soleen.com \
--cc=pratyush@kernel.org \
--cc=rppt@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.