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https://issues.apache.org/jira/browse/DERBY-5561?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13262497#comment-13262497
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Kristian Waagan commented on DERBY-5561:
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Any updates on this issue?
To me the changes look safe and correct. Given that the Connection interface
probably won't see much change, and that writing a test that reliably detects
missing synchronization in future methods (i.e. by using reflection and running
a test pattern for each method) may be non-trivial, I suggest we commit the
patch right away unless Siddharth is planning to write a test for this shortly.
Siddhart, what's your opinion on this?
> Race conditions in LogicalConnection checking for a null physical connection
> ----------------------------------------------------------------------------
>
> Key: DERBY-5561
> URL: https://issues.apache.org/jira/browse/DERBY-5561
> Project: Derby
> Issue Type: Bug
> Components: Network Client
> Affects Versions: 10.8.2.2
> Environment: Solaris 10
> Glassfish V2.1.1
> ClientXADataSource connection pool
> Reporter: Brett Bergquist
> Assignee: Siddharth Srivastava
> Labels: derby_triage10_9
> Attachments: DERBY-5561.patch
>
>
> There are race conditions with checkForNullPhysicalConnection calls in
> LogicalConnection. checkForNullPhysicalConnection is not synchronized and it
> checks for the member "phsyicalConnection" which can be cleared by
> "nullPhsyicalConnection" (which is synchronized) and "close" (which is
> synchronized) and "closeWithoutRecyclingToPool" (which is synchronized).
> This affects "nativeSQL", "getAutoCommit", "getTransactionIsolation",
> "getWarnings", "isReadOnly", "getCatalog", "getTypeMap", "createStatement",
> "prepareCall", "prepareStatement", "setHoldability", "getHoldability",
> "setSavePoint", "rollBack", "releaseSavePoint", "getSchema", "setSchema".
> All of these call "checkForNullPhysicalConnection" and then use the member
> "physicalConnection" after that call returns. Because these methods are not
> synchronized, between the time "checkForNullPhysicalConnectoin" returns and
> "physicalConnection" is used, the "physicalConnection" member could be set to
> null and then a NPE occurs.
> Probably all of these methods should be changed to synchronized.
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