Darrel Schneider created GEODE-6927:
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Summary: possible NPE in ConnectionTable.getThreadOwnedConnection
if concurrent close
Key: GEODE-6927
URL: https://issues.apache.org/jira/browse/GEODE-6927
Project: Geode
Issue Type: Bug
Components: messaging
Reporter: Darrel Schneider
ConnectionTable.getThreadOwnedConnection has a couple of usages of
"this.threadConnectionMap" that could result in an NPE if the ConnectionTable
is concurrently closed.
The unsafe code:
{code:java}
if (this.threadConnectionMap == null) {
// This instance is being destroyed; fail the operation
closeCon(
"Connection table being destroyed",
result);
return null;
}
ArrayList al = (ArrayList) this.threadConnectionMap.get(id);
if (al == null) {
// First connection for this DistributedMember. Make sure list for this
// stub is created if it isn't already there.
al = new ArrayList();
// Since it's a concurrent map, we just try to put it and then
// return whichever we got.
Object o = this.threadConnectionMap.putIfAbsent(id, al);
if (o != null) {
al = (ArrayList) o;
}
}
{code}
If a close happens after the initial null check but before either the get or
putIfAbsent call then a NPE will be thrown.
All the other code that uses "threadConnectionMap" is careful to save it into a
local var, and then use the local var. That is all that is needed here to make
this code thread safe.
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