#2029 MacOS: FG Launcher crash on aircraft change

[Fahim Dalvi]

Hello,

On OSX and the latest build from here (https://sourceforge.net/projects/flightgear/files/release-2018.2/), the launcher consistently crashes once I change my aircraft and hit Fly. I've attached the stack trace for the crashed thread (as shown by Apple's crash reporter). Thankfully the launcher remembers my new choice, so I am able to just relaunch FG and hit fly and everything works fine - which indicates some issue that is created when I switch aircrafts.

Happy to run any additional tests if required!

Here is the detailed information:

What /exactly/ did you do?

• Start FG launcher, change aircraft (either from the "recent choices" menu, or from aircraft tab). Press "Fly"

How did you expect FlightGear to respond?

• FG should launch with my selected aircraft

What did you see instead?

• FG crashes (stack trace below)

What version are you using?

• 2018.2.2

What operating system?

• MacOS High Sierra 10.13.5

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000018
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Segmentation fault: 11
Termination Reason:    Namespace SIGNAL, Code 0xb
Terminating Process:   exc handler [0]

VM Regions Near 0x18:
--> 
    __TEXT                 000000010374b000-000000010485f000 [ 17.1M] r-x/rwx SM=COW  /Applications/FlightGear.app/Contents/MacOS/fgfs

Application Specific Information:
objc_msgSend() selector name: isKindOfClass:


Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libobjc.A.dylib                 0x00007fff6951ee9d objc_msgSend + 29
1   com.apple.AppKit                0x00007fff3f8e9d22 -[NSWindow _shouldGetCornerMaskFromVisualEffectView] + 93
2   com.apple.AppKit                0x00007fff3f9ef8d8 -[NSWindow _cornerMask] + 95
3   com.apple.AppKit                0x00007fff3f9ef836 -[NSWindow _cornerMaskOrNil] + 22
4   com.apple.AppKit                0x00007fff3fa5ef22 __67-[NSWindow _updateSettingsSendingScreenChangeNotificationIfNeeded:]_block_invoke + 243
5   com.apple.AppKit                0x00007fff3f9f5c0c NSPerformVisuallyAtomicChange + 146
6   com.apple.AppKit                0x00007fff3f97b04c -[NSWindow _updateSettingsSendingScreenChangeNotificationIfNeeded:] + 193
7   com.apple.AppKit                0x00007fff3fc455f5 -[NSWindow _screenChanged:] + 58
8   com.apple.AppKit                0x00007fff3fc4557b -[NSWindow _displayChangedSoAdjustWindows:] + 159
9   com.apple.AppKit                0x00007fff3fa40138 __44-[NSApplication makeWindowsPerform:inOrder:]_block_invoke + 27
10  com.apple.AppKit                0x00007fff3fceacdd __52-[NSApplication _findWindowWithOptions:passingTest:]_block_invoke + 26
11  com.apple.AppKit                0x00007fff3fceae8c -[NSApplication enumerateWindowsWithOptions:usingBlock:] + 301
12  com.apple.AppKit                0x00007fff3fceac8a -[NSApplication _findWindowWithOptions:passingTest:] + 147
13  com.apple.AppKit                0x00007fff3f8ccbf6 -[NSApplication makeWindowsPerform:inOrder:] + 255
14  com.apple.AppKit                0x00007fff40451025 -[NSApplication(ScreenHandling) _reactToScreenInvalidationImmediately:] + 84
15  com.apple.AppKit                0x00007fff40450f95 __60-[NSApplication(ScreenHandling) _reactToScreenInvalidation:]_block_invoke + 59
16  com.apple.CoreFoundation        0x00007fff423568cc __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
17  com.apple.CoreFoundation        0x00007fff423392a3 __CFRunLoopDoBlocks + 275
18  com.apple.CoreFoundation        0x00007fff4233892e __CFRunLoopRun + 1278
19  com.apple.CoreFoundation        0x00007fff423381a3 CFRunLoopRunSpecific + 483
20  com.apple.HIToolbox             0x00007fff4161ed96 RunCurrentEventLoopInMode + 286
21  com.apple.HIToolbox             0x00007fff4161ea0f ReceiveNextEventCommon + 366
22  com.apple.HIToolbox             0x00007fff4161e884 _BlockUntilNextEventMatchingListInModeWithFilter + 64
23  com.apple.AppKit                0x00007fff3f8d0a73 _DPSNextEvent + 2085
24  com.apple.AppKit                0x00007fff40066e34 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
25  libosgViewer.131.dylib          0x000000010527c473 osgViewer::GraphicsWindowCocoa::checkEvents() + 211
26  libosgViewer.131.dylib          0x0000000105267cd4 osgViewer::Viewer::eventTraversal() + 628
27  libosgViewer.131.dylib          0x000000010526e391 osgViewer::ViewerBase::frame(double) + 97
28  org.flightgear.FlightGear       0x0000000103d90fbe fgOSMainLoop() + 126
29  org.flightgear.FlightGear       0x0000000103e00f0f fgMainInit(int, char**) + 5279
30  org.flightgear.FlightGear       0x0000000103755072 main + 290
31  org.flightgear.FlightGear       0x0000000103754d64 start + 52

Thread 1:
0   libsystem_kernel.dylib          0x00007fff6a296a1e __psynch_cvwait + 10
1   libsystem_pthread.dylib         0x00007fff6a45f589 _pthread_cond_wait + 732
2   org.flightgear.FlightGear       0x0000000103fab593 0x10374b000 + 8783251
3   org.flightgear.FlightGear       0x0000000103fab22b 0x10374b000 + 8782379
4   org.flightgear.FlightGear       0x00000001040973ca SGThread::PrivateData::start_routine(void*) + 10
5   libsystem_pthread.dylib         0x00007fff6a45e661 _pthread_body + 340
6   libsystem_pthread.dylib         0x00007fff6a45e50d _pthread_start + 377
7   libsystem_pthread.dylib         0x00007fff6a45dbf9 thread_start + 13

Thread 2:: Qt bearer thread
0   libsystem_kernel.dylib          0x00007fff6a2980a2 poll + 10
1   org.qt-project.QtCore           0x0000000106c9d8e0 qt_safe_poll(pollfd*, unsigned int, timespec const*) + 112
2   org.qt-project.QtCore           0x0000000106c9ef75 QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 885
3   org.qt-project.QtCore           0x0000000106c47781 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 401
4   org.qt-project.QtCore           0x0000000106a85eee QThread::exec() + 110
5   org.qt-project.QtCore           0x0000000106a8985a 0x106a5f000 + 174170
6   libsystem_pthread.dylib         0x00007fff6a45e661 _pthread_body + 340
7   libsystem_pthread.dylib         0x00007fff6a45e50d _pthread_start + 377
8   libsystem_pthread.dylib         0x00007fff6a45dbf9 thread_start + 13

Thread 3:: com.apple.NSEventThread
0   libsystem_kernel.dylib          0x00007fff6a28d20a mach_msg_trap + 10
1   libsystem_kernel.dylib          0x00007fff6a28c724 mach_msg + 60
2   com.apple.CoreFoundation        0x00007fff423397d5 __CFRunLoopServiceMachPort + 341
3   com.apple.CoreFoundation        0x00007fff42338b27 __CFRunLoopRun + 1783
4   com.apple.CoreFoundation        0x00007fff423381a3 CFRunLoopRunSpecific + 483
5   com.apple.AppKit                0x00007fff3fa0dfc4 _NSEventThread + 184
6   libsystem_pthread.dylib         0x00007fff6a45e661 _pthread_body + 340
7   libsystem_pthread.dylib         0x00007fff6a45e50d _pthread_start + 377
8   libsystem_pthread.dylib         0x00007fff6a45dbf9 thread_start + 13

Thread 4:
0   libsystem_kernel.dylib          0x00007fff6a297292 __workq_kernreturn + 10
1   libsystem_pthread.dylib         0x00007fff6a45e20e _pthread_wqthread + 1552
2   libsystem_pthread.dylib         0x00007fff6a45dbe9 start_wqthread + 13

Thread 5:
0   libsystem_pthread.dylib         0x00007fff6a45dbdc start_wqthread + 0

Thread 6:
0   libsystem_pthread.dylib         0x00007fff6a45dbdc start_wqthread + 0
1   ???                             0x0000400000000000 0 + 70368744177664

Thread 7:: Dispatch queue: NSCGSDisableUpdates
0   libsystem_kernel.dylib          0x00007fff6a28d20a mach_msg_trap + 10
1   libsystem_kernel.dylib          0x00007fff6a28c724 mach_msg + 60
2   com.apple.SkyLight              0x00007fff63fdeb0d CGSUpdateManager::enable_updates_common() + 565
3   com.apple.SkyLight              0x00007fff63f82c10 CGSUpdateManager::enable_update(unsigned long long) + 320
4   libdispatch.dylib               0x00007fff6a1145fa _dispatch_call_block_and_release + 12
5   libdispatch.dylib               0x00007fff6a10cdb8 _dispatch_client_callout + 8
6   libdispatch.dylib               0x00007fff6a121217 _dispatch_queue_serial_drain + 635
7   libdispatch.dylib               0x00007fff6a114166 _dispatch_queue_invoke + 373
8   libdispatch.dylib               0x00007fff6a121f0d _dispatch_root_queue_drain_deferred_wlh + 332
9   libdispatch.dylib               0x00007fff6a125d21 _dispatch_workloop_worker_thread + 880
10  libsystem_pthread.dylib         0x00007fff6a45dfd2 _pthread_wqthread + 980
11  libsystem_pthread.dylib         0x00007fff6a45dbe9 start_wqthread + 13

Thread 0 crashed with X86 Thread State (64-bit):
  rax: 0x00007fff9be9afc0  rbx: 0x00007fba0dbe7b20  rcx: 0x0000000000000000  rdx: 0x00007fff9be9afc0
  rdi: 0x00007fba0dbe7b20  rsi: 0x00007fff4055ffbb  rbp: 0x00007ffeec4b2b50  rsp: 0x00007ffeec4b2b28
   r8: 0x0000000000000001   r9: 0x0000000000000001  r10: 0x0000000000000000  r11: 0x00007fff4055ffbb
  r12: 0x00007fff6951ee80  r13: 0x00007ffeec4b2c60  r14: 0x00007fff4055ff54  r15: 0x00007fff4055ffbb
  rip: 0x00007fff6951ee9d  rfl: 0x0000000000010246  cr2: 0x0000000000000018

Logical CPU:     1
Error Code:      0x00000004
Trap Number:     14

[James Turner]

That is .... really weird. The launcher has actually finished when we crash: were into the main FGFS loop, see fgOSMainLoop.

Do you see the main FG window appear at all? And what happens if you run without the launcher?

[Fahim Dalvi]

Nop, I never see the FG window appear. I tried from the launcher with the following commands:

./fgfs --fg-root=/Applications/FlightGear.app/Contents/Resources/data/ --airport=KSFO --aircraft=c172p
./fgfs --fg-root=/Applications/FlightGear.app/Contents/Resources/data/ --airport=KSFO --aircraft=A380
./fgfs --fg-root=/Applications/FlightGear.app/Contents/Resources/data/ --airport=KSFO --aircraft=OH-1

...with the same aircraft twice, different aircraft each time etc. FG loads successfully without any issues (although almost immediately crashes after ~10 seconds - I'll post that error in a different ticket).

So it seems like this is a problem strongly connected with the launcher!

Best,
Fahim

[James Turner]

I'm still out of ideas how to fix this one - is the crash the same with a current nightly build? Otherwise trying to think what other ways we could debug / trace the issue.

[James Turner]

Chasing down old bugs: does this still happen with recent versions?

[Gijs]

Assuming that this is no longer an issue after 6 years of no further reports.