[systemd-devel] Question: systemd-resolved.service delayed almost 90s start after systemd-sysctl.service

[Paul Menzel]

Dear Alien,


Am 10.05.25 um 10:24 schrieb Alien Kong:

> I'm seeing an unexpected 90s delay between systemd-sysctl.service and
> systemd-resolved.service
> in our boot sequence (systemd 255.4-1ubuntu8.4, custom embedded board).
> 
> systemd-analyze critical-chain shows:
> multi-user.target @1min 54.340s
> └─user_medium_priority.service @1min 32.653s +21.686s
>    └─basic.target @1min 32.617s
>      └─sockets.target @1min 32.615s
>        └─ssh.socket @1min 32.614s
>          └─sysinit.target @1min 32.580s
>            └─systemd-resolved.service @1min 32.185s +394ms
>              └─systemd-sysctl.service @2.726s +89ms
>                └─systemd-modules-load.service @1.932s +577ms
>                  └─systemd-journald.socket @1.911s
>                    └─-.mount @599ms
>                      └─-.slice @598ms
> 
> We have verified no explicit dependency holding this back.
>  From the information of systemd-analyze blame, the startup time of each
> service is normal.
> 21.686s user_medium_priority.service
>   2.537s nv_duv3.service
>   1.996s dev-vblkdev30.device
>   1.993s dev-vblkdev0.device
>   1.818s dev-vblkdev2.device
>   1.766s dev-vblkdev4.device
>   1.762s dev-vblkdev5.device
>   1.670s dev-vblkdev3.device
>    794ms dev-vblkdev6.device
>    792ms dev-vblkdev15.device
>    785ms e2scrub_reap.service
>    730ms systemd-logind.service
>    711ms dev-vblkdev13.device
>    703ms dev-vblkdev8.device
>    667ms dev-vblkdev14.device
>    657ms dev-vblkdev7.device
>    635ms dev-vblkdev9.device
>    577ms systemd-modules-load.service
>    550ms systemd-networkd.service
>    394ms systemd-resolved.service
>    367ms ap-com-daemon.service
>    286ms systemd-udev-trigger.service
>    253ms user at 1000.service
>    248ms systemd-tmpfiles-setup.service
>    227ms ssh.service
>    124ms systemd-tmpfiles-clean.service
>    119ms systemd-tmpfiles-setup-dev.service
>    116ms systemd-user-sessions.service
>    114ms systemd-tmpfiles-setup-dev-early.service
> ...
> 
> Any ideas for further investigation of this situation? Thanks~
> Any insight would be appreciated.

Please paste the output of `journalctl -b` when booted with `debug` on 
the Linux kernel command line. Please also provide the service units of 
the two relevant services (`systemctl cat systemd-resolved`).


Kind regards,

Paul