Bug 742546 - RFE: a better cycle breaking strategy
Summary: RFE: a better cycle breaking strategy
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: systemd
Version: rawhide
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: systemd-maint
QA Contact: Fedora Extras Quality Assurance
Depends On:
Blocks: systemd-RFE 871527
TreeView+ depends on / blocked
Reported: 2011-09-30 14:06 UTC by Michal Schmidt
Modified: 2019-05-31 21:33 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed:
Type: ---

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Description Michal Schmidt 2011-09-30 14:06:40 UTC
+++ This bug was initially created as a clone of Bug #741115 +++
--- Additional comment from john.ellson on 2011-09-29 13:08:44 EDT
Why doesn't systemd detect cycles like this?    It seems very fragile if this kind of bug in an unrelated service can make the system near unrecoverable because services like dbus and NetworkManager fail to start.

--- Additional comment from mschmidt on 2011-09-29 16:10:10 EDT

It does. It breaks cycles by dropping a (pretty much randomly selected) member of the cycle. In https://bugzilla.redhat.com/show_bug.cgi?id=741078#c3 I showed an example where dbus.socket was the unfortunate victim.

--- Additional comment from john.ellson on 2011-09-30 09:38:25 EDT

Isn't it a cycle in a directed graph?   Shouldn't the strategy be to drop the lowest node in the cycle, rather than a random node ?    Or perhaps drop the node with the least dependencies up to that point?

Somehow I think it should cause less damage than it did in this case.

Comment 1 Fedora Admin XMLRPC Client 2011-10-20 16:31:07 UTC
This package has changed ownership in the Fedora Package Database.  Reassigning to the new owner of this component.

Comment 2 Michal Schmidt 2012-06-07 14:58:55 UTC
Some cycle-breaking suggestions in the upstream mailing list thread:

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