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https://issues.apache.org/jira/browse/QPID-4424?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13498444#comment-13498444
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Steve Huston commented on QPID-4424:
------------------------------------
It appears that PollableQueue makes an assumption that once a thread enters
dispatch() and process() that no other threads will call dispatch() until the
first one finishes. This assumption holds with (and may have been made because
of) the behavior in the epoll poller which drives the PollableQueue off of a
handle which isn't "re-armed" until the call to dispatch() completes. However,
on Windows setting the condition simply queues an I/O completion event which
may be handled immediately. So on Windows it is likely that multiple threads
will end up in dispatch() simultaneously. Since PollableQueue::process()
releases the lock while calling callback() another thread can enter dispatch()
while the previous batch is being processed.
The question is should multiple threads be allowed to dispatch events at the
same time? If so, the ordering of the callbacks may not match the order in
which they were enqueued. And if events remain after callback, the
re-enqueueing them may change the original order. I'm open to discussion of
what the desired behavior should be, but for now I'm going to propose a new
patch that prevents multiple threads from entering dispatch() at the same time,
making the Windows behavior the same as on Linux.
> C++ Broker on Windows - Assertion Failed: !dispatcher - PollableQueue.h line
> 136
> --------------------------------------------------------------------------------
>
> Key: QPID-4424
> URL: https://issues.apache.org/jira/browse/QPID-4424
> Project: Qpid
> Issue Type: Bug
> Components: C++ Broker
> Affects Versions: 0.18
> Environment: Windows Server 2008 R2 64-bit system
> Visual Studio 2010 32-bit executable
> Reporter: Chuck Rolke
> Assignee: Steve Huston
> Priority: Blocker
>
> Start broker with 'qpidd --auth no --no-data-dir'.
> Sit for 15 or so seconds. No external connections from clients. No cluster.
> Assert happens.
> Stack at assert time:
> msvcr100d.dll!_NMSG_WRITE(int rterrnum=10) Line 217 C
> msvcr100d.dll!abort() Line 61 + 0x7 bytes C
> msvcr100d.dll!_wassert(const wchar_t * expr=0x5ff25504, const wchar_t *
> filename=0x5ff25480, unsigned int lineno=136) Line 153 C
> >
> > qpidbrokerd.dll!qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> > >::dispatch(qpid::sys::PollableCondition & cond={...}) Line 136 + 0x36
> > bytes C++
>
> qpidbrokerd.dll!boost::_mfi::mf1<void,qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> >,qpid::sys::PollableCondition
> &>::operator()(qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> > * p=0x00c72b80, qpid::sys::PollableCondition & a1={...}) Line 165 + 0x10
> bytes C++
>
> qpidbrokerd.dll!boost::_bi::list2<boost::_bi::value<qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> > *>,boost::arg<1>
> >::operator()<boost::_mfi::mf1<void,qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> >,qpid::sys::PollableCondition
> &>,boost::_bi::list1<qpid::sys::PollableCondition &> >(boost::_bi::type<void>
> __formal={...},
> boost::_mfi::mf1<void,qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> >,qpid::sys::PollableCondition &> & f={...},
> boost::_bi::list1<qpid::sys::PollableCondition &> & a={...},
> boost::_bi::type<void> __formal={...}) Line 314 C++
>
> qpidbrokerd.dll!boost::_bi::bind_t<void,boost::_mfi::mf1<void,qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> >,qpid::sys::PollableCondition
> &>,boost::_bi::list2<boost::_bi::value<qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> > *>,boost::arg<1> >
> >::operator()<qpid::sys::PollableCondition>(qpid::sys::PollableCondition &
> a1={...}) Line 33 C++
>
> qpidbrokerd.dll!boost::detail::function::void_function_obj_invoker1<boost::_bi::bind_t<void,boost::_mfi::mf1<void,qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> >,qpid::sys::PollableCondition
> &>,boost::_bi::list2<boost::_bi::value<qpid::sys::PollableQueue<std::pair<boost::shared_ptr<qpid::broker::Exchange>,qpid::broker::Message>
> > *>,boost::arg<1> > >,void,qpid::sys::PollableCondition
> &>::invoke(boost::detail::function::function_buffer & function_obj_ptr={...},
> qpid::sys::PollableCondition & a0={...}) Line 154 C++
> qpidcommond.dll!boost::function1<void,qpid::sys::PollableCondition
> &>::operator()(qpid::sys::PollableCondition & a0={...}) Line 760 + 0x1a
> bytes C++
>
> qpidcommond.dll!qpid::sys::PollableConditionPrivate::dispatch(qpid::sys::windows::AsynchIoResult
> * result=0x00cad6e0) Line 81 C++
>
> qpidcommond.dll!boost::_mfi::mf1<void,qpid::sys::PollableConditionPrivate,qpid::sys::windows::AsynchIoResult
> *>::operator()(qpid::sys::PollableConditionPrivate * p=0x00c72cd0,
> qpid::sys::windows::AsynchIoResult * a1=0x00cad6e0) Line 165 + 0x10 bytes
> C++
>
> qpidcommond.dll!boost::_bi::list2<boost::_bi::value<qpid::sys::PollableConditionPrivate
> *>,boost::arg<1>
> >::operator()<boost::_mfi::mf1<void,qpid::sys::PollableConditionPrivate,qpid::sys::windows::AsynchIoResult
> *>,boost::_bi::list1<qpid::sys::windows::AsynchIoResult * &>
> >(boost::_bi::type<void> __formal={...},
> boost::_mfi::mf1<void,qpid::sys::PollableConditionPrivate,qpid::sys::windows::AsynchIoResult
> *> & f={...}, boost::_bi::list1<qpid::sys::windows::AsynchIoResult * &> &
> a={...}, boost::_bi::type<void> __formal={...}) Line 314 C++
>
> qpidcommond.dll!boost::_bi::bind_t<void,boost::_mfi::mf1<void,qpid::sys::PollableConditionPrivate,qpid::sys::windows::AsynchIoResult
> *>,boost::_bi::list2<boost::_bi::value<qpid::sys::PollableConditionPrivate
> *>,boost::arg<1> > >::operator()<qpid::sys::windows::AsynchIoResult
> *>(qpid::sys::windows::AsynchIoResult * & a1=0x00cad6e0) Line 33 C++
>
> qpidcommond.dll!boost::detail::function::void_function_obj_invoker1<boost::_bi::bind_t<void,boost::_mfi::mf1<void,qpid::sys::PollableConditionPrivate,qpid::sys::windows::AsynchIoResult
> *>,boost::_bi::list2<boost::_bi::value<qpid::sys::PollableConditionPrivate
> *>,boost::arg<1> > >,void,qpid::sys::windows::AsynchIoResult
> *>::invoke(boost::detail::function::function_buffer & function_obj_ptr={...},
> qpid::sys::windows::AsynchIoResult * a0=0x00cad6e0) Line 154 C++
>
> qpidcommond.dll!boost::function1<void,qpid::sys::windows::AsynchIoResult
> *>::operator()(qpid::sys::windows::AsynchIoResult * a0=0x00cad6e0) Line 760
> + 0x1a bytes C++
> qpidcommond.dll!qpid::sys::windows::AsynchCallbackRequest::complete()
> Line 189 C++
> qpidcommond.dll!qpid::sys::windows::AsynchResult::success(unsigned int
> bytesTransferred=0) Line 57 + 0xf bytes C++
> qpidcommond.dll!qpid::sys::Poller::wait(qpid::sys::Duration
> timeout={...}) Line 196 + 0x12 bytes C++
> qpidcommond.dll!qpid::sys::Poller::run() Line 118 C++
> qpidcommond.dll!qpid::sys::Dispatcher::run() Line 37 + 0x1d bytes
> C++
> qpidbrokerd.dll!qpid::broker::Broker::run() Line 429 + 0xb bytes
> C++
> qpidd.exe!qpid::broker::QpiddBroker::execute(qpid::broker::QpiddOptions
> * options=0x00c5b818) Line 481 + 0x26 bytes C++
> qpidd.exe!qpid::broker::run_broker(int argc=4, char * *
> argv=0x00c519f8, bool hidden=false) Line 106 + 0x16 bytes C++
> qpidd.exe!main(int argc=4, char * * argv=0x00c519f8) Line 507 + 0xf
> bytes C++
> qpidd.exe!__tmainCRTStartup() Line 555 + 0x19 bytes C
> qpidd.exe!mainCRTStartup() Line 371 C
> kernel32.dll!75d333aa()
> [Frames below may be incorrect and/or missing, no symbols loaded for
> kernel32.dll]
> ntdll.dll!770c9ef2()
> ntdll.dll!770c9ec5()
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