Reindexing fails: Cannot invoke method getValidators() on null object

Somehow we got into a situation, when Jira insists on reindexing (with exclusive locking only), but is unable to finish the job.

While the reindexing is running, the following message is spamming the log:
2014-02-27 23:11:35,485 JiraTaskExectionThread-15 WARN mteterinXXX 1388x24224x1 8zq2ol 10.187.234.6,127.0.0.1 /secure/admin/jira/IndexReIndex.jspa [atlassian.jira.index.Accumulati gResultBuilder] java.util.concurrent.ExecutionException: java.lang.NullPointerException: Cannot invoke method getValidators() on null object

It ends with the following:

Indexing completed with 12256 errors
Task completed in 3 minutes, 7 seconds with unexpected error.
Started Today 11:08 PM EST.
Finished Today 11:11 PM EST.

com.atlassian.jira.index.IndexingFailureException: Indexing completed with 12256 errors
at com.atlassian.jira.index.AccumulatingResultBuilder$CompositeResult.await(AccumulatingResultBuilder.java:147)
at com.atlassian.jira.issue.index.DefaultIndexManager.doIndexIssuesInBatchMode(DefaultIndexManager.java:877)
at com.atlassian.jira.issue.index.DefaultIndexManager.doStopTheWorldReindex(DefaultIndexManager.java:844)
at com.atlassian.jira.issue.index.DefaultIndexManager.reIndexAll(DefaultIndexManager.java:307)
at com.atlassian.jira.issue.index.DefaultIndexManager.reIndexAll(DefaultIndexManager.java:272)
at com.atlassian.jira.issue.index.DefaultIndexManager.reIndexAll(DefaultIndexManager.java:267)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.atlassian.util.profiling.object.ObjectProfiler.profiledInvoke(ObjectProfiler.java:83)
at com.atlassian.jira.config.component.SwitchingInvocationHandler.invoke(SwitchingInvocationHandler.java:28)
at $Proxy152.reIndexAll(Unknown Source)
at com.atlassian.jira.util.index.CompositeIndexLifecycleManager.reIndexAll(CompositeIndexLifecycleManager.java:56)
at com.atlassian.jira.web.action.admin.index.ReIndexAsyncIndexerCommand.doReindex(ReIndexAsyncIndexerCommand.java:28)
at com.atlassian.jira.web.action.admin.index.AbstractAsyncIndexerCommand.call(AbstractAsyncIndexerCommand.java:54)
at com.atlassian.jira.web.action.admin.index.ReIndexAsyncIndexerCommand.call(ReIndexAsyncIndexerCommand.java:16)
at com.atlassian.jira.web.action.admin.index.AbstractAsyncIndexerCommand.call(AbstractAsyncIndexerCommand.java:23)
at com.atlassian.jira.task.TaskManagerImpl$TaskCallableDecorator.call(TaskManagerImpl.java:374)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at com.atlassian.jira.task.ForkedThreadExecutor$ForkedRunnableDecorator.run(ForkedThreadExecutor.java:250)
at java.lang.Thread.run(Thread.java:722)

While we await a fix, any hint as to the work-around would be appreciated.