Found one Java-level deadlock:
=============================
"Handling POST /job/test-project-hudson-upgrade/configSubmit : http-10.233.20.50-80-144":
waiting to lock monitor 0x0000000048d52198 (object 0x000000009c2bf670, a hudson.model.FreeStyleProject),
which is held by "Project disk usage thread"
"Project disk usage thread":
waiting to lock monitor 0x0000000048f6afd0 (object 0x000000009c30a8f0, a java.util.Vector),
which is held by "Handling POST /view/orbis-solutions/job/QA_080501-Deploy/configSubmit : http-10.233.20.50-80-47"
"Handling POST /view/orbis-solutions/job/QA_080501-Deploy/configSubmit : http-10.233.20.50-80-47":
waiting to lock monitor 0x0000000048d52198 (object 0x000000009c2bf670, a hudson.model.FreeStyleProject),
which is held by "Project disk usage thread"

Java stack information for the threads listed above:
===================================================
"Handling POST /job/test-project-hudson-upgrade/configSubmit : http-10.233.20.50-80-144":
at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:555)

• waiting to lock <0x000000009c2bf670> (a hudson.model.FreeStyleProject)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:169)
  at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:101)
  at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:54)
  at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:74)
  at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
  at org.kohsuke.stapler.Stapler.invoke(Stapler.java:519)
  at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:180)
  at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
  at org.kohsuke.stapler.Stapler.invoke(Stapler.java:519)
  at org.kohsuke.stapler.Stapler.invoke(Stapler.java:435)
  ...
  at java.lang.Thread.run(Thread.java:619)
  "Project disk usage thread":
  at java.util.Vector.toArray(Vector.java:643)
• waiting to lock <0x000000009c30a8f0> (a java.util.Vector)
  at java.util.Vector.addAll(Vector.java:830)
• locked <0x00000000a4f9eb00> (a java.util.Vector)
  at hudson.model.AbstractProject.getActions(AbstractProject.java:851)
• locked <0x000000009c2bf670> (a hudson.model.FreeStyleProject)
  at hudson.model.Actionable.getAction(Actionable.java:104)
  at hudson.plugins.disk_usage.DiskUsageThread.execute(DiskUsageThread.java:55)
  at hudson.model.AsyncPeriodicWork$1.run(AsyncPeriodicWork.java:54)
  at java.lang.Thread.run(Thread.java:619)
  "Handling POST /view/orbis-solutions/job/QA_080501-Deploy/configSubmit : http-10.233.20.50-80-47":
  at hudson.model.AbstractProject.getTriggers(AbstractProject.java:1227)
• waiting to lock <0x000000009c2bf670> (a hudson.model.FreeStyleProject)
  at hudson.model.Project.updateTransientActions(Project.java:209)
• locked <0x000000009c30a8f0> (a java.util.Vector)
  at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:537)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:169)
  at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:101)
  at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:54)
  at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:74)
  at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
  at org.kohsuke.stapler.Stapler.invoke(Stapler.java:519)
  ...
  at java.lang.Thread.run(Thread.java:619)

Found 1 deadlock.