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Tomasz Krakowiak updated JBTM-2350:
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Git Pull Request:
CDI Transactional interceptors are not thread safe.
(previousUserTransactionAvailability)
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Key: JBTM-2350
URL:
https://issues.jboss.org/browse/JBTM-2350
Project: JBoss Transaction Manager
Issue Type: Bug
Components: JTA
Affects Versions: 5.0.0, 5.0.1, 5.0.2, 5.0.3, 5.0.4
Environment: Wildfly 8.1.0, Wildfly 8.2.0, linux, OS X
Reporter: Tomasz Krakowiak
Assignee: Tom Jenkinson
The problem is with availability of `UserTransaction`.
Availability of UserTransaction is stored in `ServerVMClientUserTransaction.isAvailables`
which is `ThreadLocal<Boolean>`.
`TransactionalInterceptorRequired` when intercepting call, stores thread local value of
`isAvailables` in `TransactionalInterceptorBase.previousUserTransactionAvailability` field
of interceptor - which is of type boolean(not thread local).
Here's a story:
We have a bean (beanA) with single method annotated transactional
(beanA.transactional()).
This method is being called from two threads, where:
- Thread 1 is participating in BMT, therefore it's
ServerVMClientUserTransaction.isAvailables value is true.
- Thread 2 is participating in CMT, therefore it's
ServerVMClientUserTransaction.isAvailables value is false.
Both threads call beanA.transactional() at the same time.
What may happen:
1. Thread 1 - enters method beanA.transactional.
Interceptor sets previousUserTransactionAvailability to true.
2. Thread 2 - enters method beanB.transactional.
Interceptor sets previousUserTransactionAvailability to false.
3. Thread 1 - exits method beanA.transactional
Interceptor restores thread local value of `isAvailables` to false (leaked value
from thread 2!)