Bug 66923

Summary:	generator: usage of systemctl is causing deadlock which prevents starting systemd
Product:	systemd	Reporter:	Umut Tezduyar <umut>
Component:	general	Assignee:	systemd-bugs
Status:	RESOLVED NOTABUG	QA Contact:	systemd-bugs
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Umut Tezduyar 2013-07-15 13:05:11 UTC

If systemctl is used in a generator, it causes a deadlock which eventually resolves when the bus connection request times out. But meanwhile, it prevents systemd from starting up.

A generator like following will cause deadlock.

#!/bin/sh -e

. /etc/conf.d/iptables

if [ $IPTABLES_ENABLED = yes ]; then
	systemctl --runtime --no-reload enable ip-filter.service
else
	systemctl --runtime --no-reload disable ip-filter.service
fi

Comment 1 Lennart Poettering 2013-07-15 13:41:42 UTC

You may not use systemctl or anything like that in generators. That's simply not supported.

http://www.freedesktop.org/wiki/Software/systemd/Generators/

"Since generators are run very early at boot they cannot rely on any external services. They may not talk to any other process."

I'll add a note that makes explicitly clear that systemd itself is also one of those external services.

Comment 2 Umut Tezduyar 2013-07-15 13:44:14 UTC

Thanks that would be my guess and I wanted to open a bug so we can improve documentation.

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