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https://issues.apache.org/activemq/browse/AMQCPP-207?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=47399#action_47399
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Michael J. Kitchin commented on AMQCPP-207:
-------------------------------------------
Alrighty :) I'll set it going and if we're ok at the end of the day I'll close
this out.
> Memory leak/segv's with frequent reconnections (identified)
> -----------------------------------------------------------
>
> Key: AMQCPP-207
> URL: https://issues.apache.org/activemq/browse/AMQCPP-207
> Project: ActiveMQ C++ Client
> Issue Type: Bug
> Components: CMS Impl, Decaf, Openwire
> Affects Versions: 2.2.1
> Environment: Windows XP, Vistual Studio 2005 (C++)
> Reporter: Michael J. Kitchin
> Assignee: Timothy Bish
>
> If a CMS consumer client reconnects frequently a segv will arise with
> reliability (it's guaranteed for us within a hundred reconnections or so).
> Additionally, in researching this we seem to have stumbled across a related
> memory leak.
> When we shut down our consumer in the following order, as suggested by the
> sample code:
> - delete destination
> - delete consumer
> - close session
> - close connection (*)
> - delete session
> - delete connection
> ...a segv will occur at the step marked with a (*), due to effects observable
> in these thread stack traces:
> Thread #1:
> > activemq-cppd.dll!activemq::transport::IOTransport::close() Line 158
> > C++
> activemq-cppd.dll!activemq::transport::TransportFilter::close() Line
> 222 + 0x1b bytes C++
> activemq-cppd.dll!activemq::transport::filters::TcpTransport::close()
> Line 147 + 0x8 bytes C++
>
> activemq-cppd.dll!activemq::transport::filters::ResponseCorrelator::close()
> Line 290 + 0x19 bytes C++
>
> activemq-cppd.dll!activemq::connector::openwire::OpenWireFormatNegotiator::close()
> Line 257 + 0x1b bytes C++
>
> activemq-cppd.dll!activemq::connector::openwire::OpenWireConnector::close()
> Line 178 + 0x19 bytes C++
> activemq-cppd.dll!activemq::core::ActiveMQConnectionData::close() Line
> 89 + 0x19 bytes C++
>
> activemq-cppd.dll!activemq::core::ActiveMQConnectionData::~ActiveMQConnectionData()
> Line 77 C++
> activemq-cppd.dll!activemq::core::ActiveMQConnectionData::`vector
> deleting destructor'() + 0x54 bytes C++
> activemq-cppd.dll!activemq::core::ActiveMQConnection::close() Line 160
> + 0x37 bytes C++
> Thread #2:
> activemq-cppd.dll!decaf::net::SocketInputStream::read(unsigned char *
> buffer=0x08b4dcb8, unsigned int offset=0, unsigned int bufferSize=1) Line
> 170 + 0x18 bytes C++
> > activemq-cppd.dll!decaf::io::BufferedInputStream::bufferData() Line
> > 260 + 0x30 bytes C++
> activemq-cppd.dll!decaf::io::BufferedInputStream::read(unsigned char *
> targetBuffer=0x0a80f7d8, unsigned int offset=0, unsigned int
> targetBufferSize=4) Line 181 + 0x8 bytes C++
> activemq-cppd.dll!decaf::io::DataInputStream::readAllData(unsigned char
> * buffer=0x0a80f7d8, unsigned int length=4) Line 360 + 0x25 bytes C++
> activemq-cppd.dll!decaf::io::DataInputStream::readInt() Line 167
> C++
>
> activemq-cppd.dll!activemq::connector::openwire::OpenWireFormat::unmarshal(decaf::io::DataInputStream
> * dis=0x08bd66d8) Line 227 + 0xf bytes C++
>
> activemq-cppd.dll!activemq::connector::openwire::OpenWireCommandReader::readCommand()
> Line 71 + 0x1c bytes C++
> activemq-cppd.dll!activemq::transport::IOTransport::run() Line 188 +
> 0x15 bytes C++
> activemq-cppd.dll!decaf::lang::Thread::runCallback(apr_thread_t *
> self=0x08bb3ea0, void * param=0x08bd6828) Line 113 + 0x15 bytes C++
> libapr-1.dll!dummy_worker(void * opaque=0x08bb3ea0) Line 80 C
> ...where, in thread #2, the SocketInputStream interior to the
> BufferedInputStream (the inputStream member) has been NULL'ed between two
> method calls shown below, ending at bufferedinputstream.cpp:260:
> // Get the number of bytes currently available on the input stream
> // that could be read without blocking.
> std::size_t available = inputStream->available();
> // Calculate the number of bytes that we can read. Always >= 1 byte!
> std::size_t bytesToRead = max( (std::size_t)1, min( available,
> getUnusedBytes() ) );
> // Read the bytes from the input stream.
> int bytesRead = inputStream->read( getTail(), 0, bytesToRead );
> ....as a result of the stream close() call in thread #1. The close() call is
> in place to break any waiting IO so the executor thread may terminate in an
> orderly fashion, but the stream and/or iotransport calls don't anticipate a
> case where in-stream processing is underway at the time its internal state is
> reset.
> This suggests either:
> (1) more careful synchronization of the compound stream's state
> (2) realigning the compound stream's member data
> ...I would vote the former, and could suggest some options.
> Additionally, when reviewing the code in in thread #1 we found the following,
> beginning at iotransport.cpp:150:
> // We have to close the input stream before
> // we stop the thread. this will force us to
> // wake up the thread if it's stuck in a read
> // (which is likely). Otherwise, the join that
> // follows will block forever.
> if( inputStream != NULL ){
> inputStream->close();
> inputStream = NULL;
> }
> // Wait for the thread to die.
> if( thread != NULL ){
> thread->join();
> delete thread;
> thread = NULL;
> }
> // Close the output stream.
> if( outputStream != NULL ){
> outputStream->close();
> outputStream = NULL;
> }
> ...our familiarity with decaf is limited, but it appears inputStream and
> outputStream are conventional pointers, so should therefore be deleted prior
> to being set to NULL to avoid leaking memory. To minimize the other potential
> segv edge cases, we would suggest doing the close() calls before completing
> the thread join(), then deleting/NULL'ing the pointers afterwards.
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