Description Andrey Loskutov 2020-11-04 09:47:51 EST

Another MT issue I've stumbled upon while debugging bug 566262.
A common pattern in the JDT indexer code is to check if there is already an indexing request for same library pending and to submit after that check.

However, the check is not atomic, means it is not inside any synchronized code:

if (!isJobWaiting(request))
	request(request);

Any thread can add new request between if condition is evaluated and request() call.

See for example
org.eclipse.jdt.internal.core.search.indexing.IndexManager.indexLibrary(IPath, IProject, URL, boolean)