Bug 26698

Summary:	Deadlock involving dbus-python and some other thread. Needs debugging.
Product:	Telepathy	Reporter:	David Laban <david.laban>
Component:	fargo	Assignee:	David Laban <david.laban>
Status:	RESOLVED FIXED	QA Contact:	Simon McVittie <smcv>
Severity:	normal
Priority:	medium	Keywords:	patch
Version:	unspecified
Hardware:	Other
OS:	All
URL:	http://git.collabora.co.uk/?p=user/alsuren/telepathy-fargo.git;a=shortlog;h=refs/heads/deadlock
Whiteboard:	review+
i915 platform:		i915 features:

Description David Laban 2010-02-22 06:47:56 UTC

Currently we have a deadlock which is worked around with a watchdog in telepathy_fargo.tac. This makes me very sad, and makes it hard to keep the process alive for long enough to properly benchmark it.

This is what I am currently working on. Expect a patch to dbus-python or something soon.

Comment 1 David Laban 2010-02-25 12:18:24 UTC

After a most excellent adventure into gdb+python, via http://dmalcolm.livejournal.com/4545.html and recompiling python2.5 from source, I managed to isolate the bug and fix it. While the deadlock happens because of a non-reentrant lock in dbus python, I don't think a reentrant lock would be safe, so I just pushed unregistering into an idle.

I should probably do some more load testing just to make sure we don't have any other sneaky deadlocks.

Comment 2 Simon McVittie 2010-02-25 13:50:56 UTC

This is terrifying, but looks OK. Ship it, and if you can suggest an improvement to dbus-python, please do so.

Comment 3 Simon McVittie 2010-03-17 05:49:56 UTC

Did you merge this in the end?

Comment 4 David Laban 2010-03-22 05:40:43 UTC

Oops: not pushed to origin. Done now. Closing.

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