RTMPSession::write() (intermittently) called after RTMPSession::~RTMPSession()

[jeffreywescott]

It is intermittently reproducible using the SampleBroadcaster project. Just repeatedly press the Connect / Disconnect button over and over again and it will eventually happen.

m_streamSession's internal pointer is NULL, so everything crashes.

Thread 1, Queue : com.apple.main-thread (check out frame #5)

#0  0x385ff544 in __semwait_signal ()
#1  0x38668660 in pthread_join ()
#2  0x379f7284 in std::__1::thread::join() ()
#3  0x0010e580 in ~JobQueue at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/BuildHeaders/VideoCore/videocore/system/JobQueue.hpp:68
#4  0x001070c8 in ~JobQueue at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/BuildHeaders/VideoCore/videocore/system/JobQueue.hpp:65
#5  0x00122a4a in ~RTMPSession at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/rtmp/RTMPSession.cpp:85
#6  0x001227fc in ~RTMPSession at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/rtmp/RTMPSession.cpp:80
#7  0x001227dc in ~RTMPSession at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/rtmp/RTMPSession.cpp:80
#8  0x001471a0 in std::__1::default_delete<videocore::RTMPSession>::operator()(videocore::RTMPSession*) const [inlined] at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2426
#9  0x0014718e in std::__1::__shared_ptr_pointer<videocore::RTMPSession*, std::__1::default_delete<videocore::RTMPSession>, std::__1::allocator<videocore::RTMPSession> >::__on_zero_shared() at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:3669
#10 0x379ebd78 in std::__1::__shared_weak_count::__release_shared() ()
#11 0x0014035e in ~shared_ptr at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:4448
#12 0x001402d8 in ~shared_ptr at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:4446
#13 0x0013b5d6 in std::__1::shared_ptr<videocore::IOutputSession>::reset() [inlined] at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:4577
#14 0x0013b540 in -[VCSimpleSession endRtmpSession] at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/api/iOS/VCSimpleSession.mm:330
#15 0x000f90ca in -[ViewController btnConnectTouch:] at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/SampleBroadcaster/ViewController.mm:72
#16 0x301166a6 in -[UIApplication sendAction:to:from:forEvent:] ()
#17 0x30116642 in -[UIApplication sendAction:toTarget:fromSender:forEvent:] ()
#18 0x30116612 in -[UIControl sendAction:to:forEvent:] ()
#19 0x30101d5a in -[UIControl _sendActionsForEvents:withEvent:] ()
#20 0x3011605a in -[UIControl touchesEnded:withEvent:] ()
#21 0x30115d2c in -[UIWindow _sendTouchesForEvent:] ()
#22 0x30110c86 in -[UIWindow sendEvent:] ()
#23 0x300e5e54 in -[UIApplication sendEvent:] ()
#24 0x300e4520 in _UIApplicationHandleEventQueue ()
#25 0x2d87afae in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ ()
#26 0x2d87a476 in __CFRunLoopDoSources0 ()
#27 0x2d878c66 in __CFRunLoopRun ()
#28 0x2d7e3728 in CFRunLoopRunSpecific ()
#29 0x2d7e350a in CFRunLoopRunInMode ()
#30 0x327526d2 in GSEventRunModal ()
#31 0x30144870 in UIApplicationMain ()
#32 0x000f93e6 in main at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/SampleBroadcaster/main.m:33

Thread 31 com.videocore.rtmp, Queue : (null) (check out frame #0)

#0  0x001234a2 in videocore::RTMPSession::write(unsigned char*, unsigned long) at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/rtmp/RTMPSession.cpp:181
#1  0x0012814e in operator() at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/VideoCore/rtmp/RTMPSession.cpp:298
#2  0x001280d8 in decltype(std::__1::forward<videocore::RTMPSession::streamStatusChanged(long)::$_3&>(fp)(std::__1::forward<>(fp0))) std::__1::__invoke<videocore::RTMPSession::streamStatusChanged(long)::$_3&>(videocore::RTMPSession::streamStatusChanged(long)::$_3&&&) [inlined] at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/__functional_base:413
#3  0x001280ce in std::__1::__function::__func<videocore::RTMPSession::streamStatusChanged(long)::$_3, std::__1::allocator<videocore::RTMPSession::streamStatusChanged(long)::$_3>, void ()>::operator()() at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/functional:1370
#4  0x00110b78 in std::__1::function<void ()>::operator()() const at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/functional:1755
#5  0x00110b00 in videocore::Job::operator()() const at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/BuildHeaders/VideoCore/videocore/system/JobQueue.hpp:45
#6  0x001109a4 in videocore::JobQueue::thread() at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/BuildHeaders/VideoCore/videocore/system/JobQueue.hpp:103
#7  0x0011085c in operator() at /Users/jeffrey/dev/cine-dev/VideoCore/sample/SampleBroadcaster/Pods/BuildHeaders/VideoCore/videocore/system/JobQueue.hpp:62
#8  0x0011071a in std::__1::__thread_proxy<std::__1::tuple<videocore::JobQueue::JobQueue()::'lambda'()> >(void*, void*) at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2602
#9  0x38666958 in _pthread_body ()
#10 0x386668ca in _pthread_start ()

[jgh-]

Yes I've seen this as well, I'll put in a fix to make sure that doesn't happen.

[jgh-]

I added a barrier when the session is ending to prevent further writes from being queued

[jeffreywescott]

Awesome. I'll test it out.

Do you think you'll be uploading a new CocoaPod to trunk?

[jgh-]

Yeah I can do a new one tonight or something with this fix and the other PR's from the past day or so.