On Fri, Aug 14, 2026 at 02:31:28AM -0700, Shradha Gupta wrote: > Kexec reboot consistently fails on ARM64 Hyper-V guests (Azure VMs). > During the kexec shutdown path, VMBus channels are never cleaned up, > so in the fresh kexec kernel startup hv_acpi_init() blocks because > the hypervisor still holds the old kernel's VMBus session open. > > This is because ARM64 lacks the VMBus teardown that x86 performs during > kexec via hv_machine_shutdown(). On x86, machine_ops.shutdown is > overridden to send CHANNELMSG_UNLOAD and disable SynIC before CPUs > go offline. ARM64 has no equivalent mechanism.
I'm really not keen on such hook, a bare pointer you set elsewhere. Not sure it was discussed before but can you not use the syscore_shutdown() mechanism? This hook got added in 2023, so the 2022 discussion you referenced precedes it. -- Catalin
