[Boost-bugs] [Boost C++ Libraries] #7580: boost::asio::tcp SEGV after ioservice stopped, restarted and new

Subject: [Boost-bugs] [Boost C++ Libraries] #7580: boost::asio::tcp SEGV after ioservice stopped, restarted and new
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-10-27 12:34:52

#7580: boost::asio::tcp SEGV after ioservice stopped, restarted and new
------------------------------+---------------------------------------------
 Reporter:  tobi@…            |        Type:  Bugs            
   Status:  new               |   Milestone:  To Be Determined
Component:  None              |     Version:  Boost 1.50.0    
 Severity:  Problem           |    Keywords:                  
------------------------------+---------------------------------------------
 For solarpowerlog [1] I use boost::asio for the communication via TCP/IP.
 During an implementation of an new feature I experienced an reproducible
 segfault when during ioservice->poll()

 I hope to give enough information to dig into, but if you need some
 additional information, please let me know.

 Please let me also know if I am (unknowingly) misuse or use the library
 wrongly.

 Thanks
 coldtobi

 '''What I am doing:'''

 The feature is for sharing a TCP/IP connection within several data
 sources/sinks in the programm. For this implementation every data source
 can write and receive at abitrary times where sends have priority over
 receives. This is realized in the way that receives are interrupted if
 another data source request a write and then the receive is resumed. The
 handling of the TCP/IP i/o is done in an dedicated thread (I mark this
 "[T]" below) , the interruption in the "main" process (marked [M])

 So basically the programm does:
 [T] socket->connect()
 [T] socket->async_write(); (in parallel running a deadline_timer to catch
 timeouts)
 [T] socket->read_some(); (in parallel running a deadline_timer to catch
 timeouts. Later we will socket->read_some again after we know the amount
 of pending bytes.  and read those. But for this report: The interruption
 (next step) is usually at the first read_some() )
 [M] ioservice->stop(); (this aborts the read_some, )

 Here the thread making the IO detects that the ioservice has been stopped
 via ioservice->stopped() and will then abort the current operation, wait
 for the next request adn  before executing this new request it will call
 ioservice->reset():

 [t] ioservice->reset()

 As we now close to the crash, I will elabaroate as precise as possible
 what is done. (This all now is in the I/O thread)

 Note: You can find the code at [3]. I add line numbers for better
 orientation

 creating the deadline-timer: (lines 684+)

 {{{
         deadline_timer timer(*(this->ioservice));
         boost::posix_time::time_duration td =
 boost::posix_time::millisec(timeout);
         timer.expires_from_now(td);
         timer.async_wait(boost::bind(&boosthelper_set_result, (int*)
 &result_timer,
                         1));
 }}}
 (boosthelper_set_result is defined in line 451 and just set result_timer
 to 1 if called)

 write the bytes: (line 692+)
 {{{

         boost::asio::async_write(*sockt, boost::asio::buffer(s),
 write_handler);
 }}}
 s is a std::string and contains the data to be sent. max 255 bytes ASCII)

 run the ioservice once to either finish the write or the timeout (line
 695)

 {{{
         size_t num = ioservice->run_one(ec);
 }}}

 run_once returns and the evaluation shows that async_write completed
 -- num!=0 is checked and the result_timer also

 Observation: Wireshark shows that the bytes are not transmitted

 Then the timer is cancelled and its completion handler catched: (line
 703+)
 {{{
  timer.cancel();
  LOGTRACE(logger, __PRETTY_FUNCTION__ << ": still alive 2f");
  ioservice->poll();
  LOGTRACE(logger, __PRETTY_FUNCTION__ << ": still alive 3");

 }}}

  ioservice->poll() is never returning, SEGV is raised here. Unfortunatly
 the backtrace is also corrupted.


 When not calling the ioservice->stop(), the SEGFAULT is gone too.
 (Confirmed by working around the need to stop the ioservice by just
 polling with short timeouts)

 '''Testcase'''
 Providing a destilled testcase is unfortuantly difficult. However, you can
 use solarpowerlog to see the issue. I commmited also sample configuration
 which allows a easy reproduction of the issue. See the git tree here [2].

 If you have debian, you can install the build-dependencies by '''apt-get
 build-dep solarpowerlog'''
 Otherwise configure will tell you about missing deps :-)


 {{{
 git clone
 git://solarpowerlog.git.sourceforge.net/gitroot/solarpowerlog/solarpowerlog
 cd solarpowerlog
 git checkout 47c079d3409c867287888f47bedb4f05b1c353b5
 ./bootstrap.sh
 ./configure --enable-sharedcomms --enable-sputniksimulator --enable-
 dummyinverter
 make
 # in one shell (this one will not crash)
 src/solarpowerlog -c tools/sputnik_simulator/solarpowerlog_shared.conf
 # in another shell: (this one which will crash)
 src/solarpowerlog -c example_confs/solarpowerlog_shared_sim.conf
 }}}


 After some seconds youl'll see the SEGV:

 {{{
 12839 [0x7f2cc3345760] DEBUG
 inverter.Simulator2.Comms_SharedConnection.SharedTarget null - virtual
 void CSharedConnectionSlave::Send(ICommand*): work: 0x7f2cb8003550
 12839 [0x7f2cc3345760] DEBUG
 inverter.Simulator2.Comms_SharedConnection.SharedTarget null -  Not atomic
 0x7f2cb8003550
 12839 [0x7f2cc3345760] DEBUG
 inverter.Simulator2.Comms_SharedConnection.SharedTarget null - virtual
 void CSharedConnectionSlave::Send(ICommand*): submitting work:
 0x7f2cb8003550
 12839 [0x7f2cc3345760] DEBUG
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - virtual
 bool CConnectTCPAsio::AbortAll() Aborting 0 backlog entries
 12839 [0x7f2cc3345760] DEBUG
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - virtual
 bool CConnectTCPAsio::AbortAll() Done
 12839 [0x7f2cc3345760] DEBUG inverter.Simulator.Comms_SharedConnection.
 null - Ticket for this command is: 0 (current ticket is 0)
 12839 [0x7f2cc3345760] DEBUG inverter.Simulator.Comms_SharedConnection.
 null - CSharedConnectionMaster::Send() ICmd: 0x7f2cb8003550
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - ioservice
 stopped (1)
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - Waiting
 for work
 12964 [0x7f2cbfea1700] DEBUG
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - ioservice
 stopped
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - void
 CConnectTCPAsio::HandleSend(CAsyncCommand*): now handling: 0x7f2cb8003550
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - void
 CConnectTCPAsio::HandleSend(CAsyncCommand*): still alive 1
 12964 [0x7f2cc3345760] DEBUG inverter.Simulator.Comms_SharedConnection.
 null - virtual void CSharedConnectionMaster::ExecuteCommand(const
 ICommand*) now handling: 0x7f2cb8004460
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - void
 CConnectTCPAsio::HandleSend(CAsyncCommand*): still alive 2
 12964 [0x7f2cc3345760] DEBUG inverter.Simulator.Comms_SharedConnection.
 null - virtual void CSharedConnectionMaster::ExecuteCommand(const
 ICommand*) rescheduling read: 0x7f2cb8003e30
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - void
 CConnectTCPAsio::HandleSend(CAsyncCommand*): still alive 2e
 12964 [0x7f2cbfea1700] TRACE
 inverter.Simulator.Comms_SharedConnection..Comms_TCP_ASIO null - void
 CConnectTCPAsio::HandleSend(CAsyncCommand*): still alive 2f
 src/solarpowerlog Segmentation fault.
 }}}


 [1] http://sourceforge.net/projects/solarpowerlog/


 [2]
 http://solarpowerlog.git.sourceforge.net/git/gitweb.cgi?p=solarpowerlog/solarpowerlog;a=commit;h=47c079d3409c867287888f47bedb4f05b1c353b5


 [3]
 http://solarpowerlog.git.sourceforge.net/git/gitweb.cgi?p=solarpowerlog/solarpowerlog;a=blob;f=src/Connections/CConnectTCPAsio.cpp;h=5e3b0a1b13b66cc07e491ed98ad7dfe1f3cc5277;hb=47c079d3409c867287888f47bedb4f05b1c353b5

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