[MNG-6323] Deadlock in multithreaded dependency resolution

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.5.2
• Fix Version/s: 3.5.3
• Assignee: Robert Scholte
• Reporter: Ben Caradoc-Davies
• Created: 18/Dec/17 19:18
• Updated: 28/Mar/20 15:02
• Resolved: 20/Feb/18 17:24

Description

Maven 3.5.2 multithreaded builds experience a deadlock not seen with Maven 3.5.0.

To reproduce the issue, clone GeoServer:

git clone https://github.com/geoserver/geoserver.git
cd geoserver

Build GeoServer community modules with:

mvn -f src/community/pom.xml -B -T4 -U -Prelease -PcommunityRelease -DskipTests clean install

Builds that normally take 2-4 minutes instead experience long hangs. jstack output (attached) suggests a deadlock (two different hangs attached). Some of the locks are in TIME_WAIT and eventually the build completes after 30-45 minutes, but this is enough to cause builds on Travis to be killed for their failure to output for ten minutes. (Travis upgraded to Maven 3.5.2 a week ago.)

I have only seen the failures with -U. The hang does not occur in single-threaded builds. There are no "*.lock" files in the local repository during the hang so the deadlocks are not mediated by the filesystem. CPU utilisation is zero suggesting a deadlock not a livelock.

See also discussion on the geoserver-devel mailing list: http://osgeo-org.1560.x6.nabble.com/Travis-failures-started-with-new-trusty-images-td5346836.html

Issue Links

• is duplicated by: MNG-6418 Parallel builds with empty local repository hang
• is duplicated by: MNG-6324 multithread build: DefaultProjectDependenciesResolver.resolve waits for a lock indenfinetly causing the build to hang
• is duplicated by: MNG-6361 Multithreaded Build hangs for 10+ Minutes, then resumes
• relates to: MRESOLVER-39 deadlock during multithreaded dependency resolution