[BEEHIVE-1231] Apache Beehive concurrent use of unsynchronized HashMap can cause threads to go into an infinite loop.

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.0.2
• Component/s: NetUI
• Assignee: Unassigned
• Reporter: Michael Speer
• Created: 12/Oct/09 18:09
• Updated: 12/Oct/09 18:09

Description

Apache Beehive concurrent use of unsynchronized HashMap can cause threads to go into an infinite loop.
Description: The observed behavior is STUCK threads with the following stack trace (first N lines of):

at java.util.HashMap.get(HashMap.java:346)
at org.apache.beehive.netui.pageflow.interceptor.action.ActionInterceptorContext.getActionInterceptors(ActionInterceptorContext.java:159)
at org.apache.beehive.netui.pageflow.PageFlowRequestProcessor.processActionPerform(PageFlowRequestProcessor.java:2066)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at org.apache.beehive.netui.pageflow.PageFlowRequestProcessor.processInternal(PageFlowRequestProcessor.java:556)
at org.apache.beehive.netui.pageflow.PageFlowRequestProcessor.process(PageFlowRequestProcessor.java:853)
at org.apache.beehive.netui.pageflow.AutoRegisterActionServlet.process(AutoRegisterActionServlet.java:631)
at org.apache.beehive.netui.pageflow.PageFlowActionServlet.process(PageFlowActionServlet.java:158)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
...

The problem occurs when (some unknown) ill synchronized concurrent access to the HashMap produces a loop in the Entry "e.next" data members, causing the get() code to loop:

public V get(Object key) {
if (key == null)
return getForNullKey();
int hash = hash(key.hashCode());
for (Entry<K,V> e = table[indexFor(hash, table.length)];
e != null;
e = e.next)

{ Object k; if (e.hash == hash && ((k = e.key) == key || key.equals(k))) return e.value; }

return null;
}