Bug#1148952: linux: enable opt-in Kexec Handover and Live Update Orchestrator

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From	Artem Prilutskiy <cyanide.burnout@gmail.com>
Newsgroups	linux.debian.bugs.dist, linux.debian.kernel
Subject	Bug#1148952: linux: enable opt-in Kexec Handover and Live Update Orchestrator
Date	Fri, 25 Sep 2026 17:20:01 +0200
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Package: src:linux
Version: 7.2.7-1
Severity: wishlist

Please consider enabling the following options in Debian kernel builds on architectures that support them (in particular amd64 and arm64):

CONFIG_KEXEC_HANDOVER=y
CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT=n
CONFIG_LIVEUPDATE=y
CONFIG_LIVEUPDATE_MEMFD=y

The default-off setting is intentional. Kexec Handover should remain opt-in through the kho=on kernel parameter; Live Update Orchestrator likewise requires liveupdate=on. This makes the facilities available without changing the default behavior or requiring users to rebuild Debian kernels.

Our use case is a stateful service that stores application state in memfds held by systemd's file descriptor store. That state includes many UDP connection contexts. With KHO and LUO, a new kernel and service instance can recover the same memfd-backed state across kexec. This does not require the kernel to preserve the UDP sockets themselves. We have exercised the handover with a custom 7.2.7 kernel in a Debian sid KVM guest; stock Debian kernels do not currently expose these options.

The options are provided upstream and remain gated by the required architecture and feature dependencies. Enabling them in Debian would let interested users test and deploy this mechanism explicitly, while leaving normal boots unchanged.

Upstream documentation: https://docs.kernel.org/core-api/liveupdate.html

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Bug#1148952: linux: enable opt-in Kexec Handover and Live Update Orchestrator Artem Prilutskiy <cyanide.burnout@gmail.com> - 2026-09-25 17:20 +0200
  Processed: Re: Bug#1148952: linux: enable opt-in Kexec Handover  and Live Update Orchestrator "Debian Bug Tracking System" <owner@bugs.debian.org> - 2026-09-26 11:10 +0200
  Bug#1148952: linux: enable opt-in Kexec Handover and Live Update Orchestrator Salvatore Bonaccorso <carnil@debian.org> - 2026-09-26 11:10 +0200

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