0007546: WeakRegistry deadlock during finalization

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Category

Severity

Reproducibility

Date Submitted

Last Update

0007546

[Squeak] Kernel

major

always

06-13-10 08:08

02-06-11 23:48

Reporter

JoachimGeidel

View Status

public

Assigned To

leves

Priority

normal

Resolution

fixed

Status

closed

Product Version

4.1

Summary

0007546: WeakRegistry deadlock during finalization

Description

In Squeak 4.1, I encountered a deadlock problem related to Squeak's current
WeakRegistry implementation when the JVM is started. This problem
disappeared when I changed the finalizationProcess of WeakArray such that it
runs at systemBackgroundPriority instead of userBackgroundPriority. However, normal processes (with priority 40) could starve the finalization
process if it's priority were <= 40 (#systemBackgroundPriority is 20).

To reproduce, load JNIPort into Squeak 4.1, and start a JVM as described on http://www.squeaksource.com/JNIPort.html. [^] At the point where the deadlock occurs, the finalizationProcess sends #wait to the accessLock of WeakRegistry, then the Process which initializes the JVM waits on the same Semaphore until the process is interrupted by a user interrupt. After proceeding, the interrupted process proceeds, signals the accessLock, and only after this, the finalizationProcess finishes finalizeValues and signals the accessLock. Lowering the priority of the finalizationProcess works around this problem, but probably simply by completely stopping finalization until the JVM initialization has finished.

Additional Information

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Notes
(0013818 - 28 - 28 - 28 - 28 - 28 - 28) leves 06-19-10 20:41	Fixed in Collections-ul.365.

Issue History
Date Modified	Username	Field	Change
06-13-10 08:08	JoachimGeidel	New Issue
06-19-10 20:41	leves	Note Added: 0013818
06-19-10 20:42	leves	Status	new => resolved
06-19-10 20:42	leves	Fixed in Version	=> trunk
06-19-10 20:42	leves	Resolution	open => fixed
06-19-10 20:42	leves	Assigned To	=> leves
02-06-11 23:48	leves	Status	resolved => closed

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