Could you boot the system with udev.log_priority=debug kernel command line option?

I have no idea what rk3399 is exactly, but this looks more likely to be some compiler mismatch rather then a specific systemd problem. Everything seems to be segfaulting.

Created attachment 1667290 [details]
rdsosreport.txt with udev.log_priority=debug applied

RK3399 is a System on Chip (SoC) [1] equipped on e.g. several Single Bord Computer (SBC).

[1] http://opensource.rock-chips.com/wiki_RK3399

udevd starts, parses config, starts one worker, and immediately segfaults:
[    8.742891] localhost system\00d-udevd[510]: /etc/udev/rules.d/65-md-incremental-imsm.rules:23 PROGRAM key takes '==' or '!=' operator, assuming '=='.
[    8.743097] localhost systemd-udevd[510]: Reading rules file: /usr/lib/udev/rules.d/66-kpartx.rules
[    8.743317] localhost systemocalhost systemd-udevd[510]: Successfully forked off 'n/a' as PID 576.
[    8.756743] localhost systemd-udevd[510]: clockevents: Worker [576] is forked for processing SEQNUM=1244.
[    8.756913] localhost systemd-udevd[575]: amba: Device (SEQNUM=1239, ACTION=add) processed
[    8.757069] localhost systemd-udevd[575]: amba: sd-device-monitor: Passed 133 byte to netlink monitor
[    8.757226] localhost systemd-udevd[510]: clocksource: Device (SEQNUM=1245, ACTION=add) is queued
[    8.757990] localhost audit[576]: ANOM_ABEND auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=576 comm="systemd-udevd" exe="/usr/lib/systemd/systemd-udevd" sig=11 res=1
[    8.758395] localhost systemd-udevd[510]: Successfully forked off 'n/a' as PID 578.
[    8.758700] localhost systemd-udevd[510]: clocksource: Worker [578] is forked for processing SEQNUM=1245.

I think then systemd restarted udevd and the whole process repeats.
This seems very predictable. Maybe you could try to run udev by hand:
stop systemd-udevd.service, and invoke 'valgrind  'gdb /usr/lib/systemd/systemd-udevd'
or 'gdb /usr/lib/systemd/systemd-udevd' manually,
and possibly trigger events with 'udevadm trigger'. We should get a backtrace then.

I doubt that I am able to fulfill your request. The initramfs probably does not include gdb. I do not spot any sdhci traces in the log (the entire system code resides on the micro-SD-card). I don't know how to get access to the persistent rootfs at this stage.

I have Fedora running on a number of rk3399 devices with no issues, can you provide more details of the hardware. Also I suggest running Fedora 33 GA [1], the Feb f-32 nightly is a little out of date.

[1] https://alt.fedoraproject.org/alt/

My NanoPC-T4 is running a fully featured Fedora desktop for a long time now, and with alc5651 audio jack and Typec USB support (Fedora lacks the required configuration therefor).
After [1] and renaming the bug summary, so my comment looks stupid, I lost any motivation to report my findings back. I had only followed the advice to look for open bugs before opening a new one. In the end systemd was not the culprit and this report can be closed.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1810134#c5

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