[systemd-devel] systemctl kexec doing normal reboot (POST)

[Paul Menzel]

Dear Ian,

Am 10.08.25 um 19:48 schrieb Ian Pilcher:
> I'm playing around, trying to use 'systemctl kexec' for faster reboots.
> Thus far, I haven't been able to get it to work; I'm always getting a
> "normal" reboot (including the firmware POST).
> 
> My system (Fedora 42) is using UEFI boot, with secure boot disabled.
> systemd-boot is the bootloader.
> 
>> $ sudo bootctl --no-pager
>> System:
>>       Firmware: UEFI 2.40 (American Megatrends 5.10)
>>  Firmware Arch: x64
>>    Secure Boot: disabled (setup)
>>   TPM2 Support: no
>>   Measured UKI: no
>>   Boot into FW: supported
>>
>> Current Boot Loader:
>>       Product: systemd-boot 257.7-1.fc42
>>      Features: ✓ Boot counting
>>                ✓ Menu timeout control
>>                ✓ One-shot menu timeout control
>>                ✓ Default entry control
>>                ✓ One-shot entry control
>>                ✓ Support for XBOOTLDR partition
>>                ✓ Support for passing random seed to OS
>>                ✓ Load drop-in drivers
>>                ✓ Support Type #1 sort-key field
>>                ✓ Support @saved pseudo-entry
>>                ✓ Support Type #1 devicetree field
>>                ✓ Enroll SecureBoot keys
>>                ✓ Retain SHIM protocols
>>                ✓ Menu can be disabled
>>                ✓ Multi-Profile UKIs are supported
>>                ✓ Boot loader set partition information
>>     Partition: /dev/disk/by-partuuid/e3cdac2c-91c9-4be9-abdd-b97a9dea16f0
>>        Loader: └─/EFI/SYSTEMD/SYSTEMD-BOOTX64.EFI

[…]

> I don't see any obviously fatal errors when I do a dry run.
> 
>> $ sudo SYSTEMD_LOG_LEVEL=debug systemctl --dry-run kexec

[…]

>> Would run /usr/sbin/kexec --load "/efi/e74ab0d2949c479eb03abdab1b1acd41/6.15.9-201.fc42.x86_64/linux" --append "root=/dev/mapper/vg_breadbox-lv_fedora ro rd.lvm.lv=vg_breadbox/lv_fedora elevator=deadline intel_iommu=on systemd.machine_id=e74ab0d2949c479eb03abdab1b1acd41" --initrd "/efi/e74ab0d2949c479eb03abdab1b1acd41/6.15.9-201.fc42.x86_64/initrd"
>> Would set wall message "".
>> Would execute org.freedesktop.login1.Manager RebootWithFlags dbus call.
>> Bus n/a: changing state RUNNING → CLOSED
> 
> Nonetheless, running 'systemctl kexec' is doing a normal reboot,
> including the firmware POST.
> 
> Any pointers on how to troubleshoot this further would be appreciated.

What happens if you run the kexec command from above manually?


Kind regards,

Paul