6.9.0 crashes when app is terminated by the user

[salling]

1. Background the app while video is playing (picture in picture)
2. Swipe to terminate the app
3. App doesn't terminate immediately and is then "watchdog-killed" because it failed to finish.

We found this issue in our internal testing before releasing. We have confirmed that 6.8.1 does not have this issue, and have reverted to using that version instead.

I have attached crash logs. Some symbols and threads redacted.

Please do something about the quality situation in this library. We had high hopes that 6.9.0 would fix long standing crasher issues, but it just seems to have made things worse. Here's what our current top crasher situation looks like:

As you can see, a single library (comscore) is responsible for an order of magnitude more crashers than the rest of the app. That's unacceptable, IMHO.

Exception Type:  EXC_CRASH (SIGKILL)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Termination Reason: FRONTBOARD 2343432205 
<RBSTerminateContext| domain:10 code:0x8BADF00D explanation:[application<REDACTED>:27415] failed to terminate gracefully after 5.0s
ProcessVisibility: Unknown
ProcessState: Running
WatchdogEvent: process-exit
WatchdogVisibility: Background
WatchdogCPUStatistics: (
"Elapsed total CPU time (seconds): 7.450 (user 4.380, system 3.070), 24% CPU",
"Elapsed application CPU time (seconds): 0.433, 1% CPU"
) reportType:CrashLog maxTerminationResistance:Interactive>

Triggered by Thread:  0

Kernel Triage:
VM - Compressor failed a blocking pager_get
VM - Compressor failed a blocking pager_get


Thread 0 name:   Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libsystem_kernel.dylib        	       0x1b82ca6cc __psynch_mutexwait + 8
1   libsystem_pthread.dylib       	       0x1f1d973cc _pthread_mutex_firstfit_lock_wait + 84
2   libsystem_pthread.dylib       	       0x1f1d9e50c _pthread_mutex_firstfit_lock_slow + 240
3   ComScore                      	       0x105c17d5c ComScore::CriticalSection::enter() const + 12
4   ComScore                      	       0x105b987dc ComScore::TaskExecutor::shutdown() + 120
5   ComScore                      	       0x105bacb60 ComScore::Core::shutDown() + 24
6   ComScore                      	       0x105bd3348 ComScore::CoreContainer::~CoreContainer() + 24
7   libsystem_c.dylib             	       0x18c1c88c4 __cxa_finalize_ranges + 460
8   libsystem_c.dylib             	       0x18c1c3228 exit + 32
9   UIKitCore                     	       0x184175df0 -[UIApplication _terminateWithStatus:] + 504
10  UIKitCore                     	       0x183862544 -[_UISceneLifecycleMultiplexer _evalTransitionToSettings:fromSettings:forceExit:withTransitionStore:] + 128
11  UIKitCore                     	       0x183a57d94 -[_UISceneLifecycleMultiplexer forceExitWithTransitionContext:scene:] + 224
12  UIKitCore                     	       0x18417296c -[UIApplication workspaceShouldExit:withTransitionContext:] + 212
13  FrontBoardServices            	       0x192ec8c48 __63-[FBSWorkspaceScenesClient willTerminateWithTransitionContext:]_block_invoke_2 + 80
14  FrontBoardServices            	       0x192e836c4 -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] + 240
15  FrontBoardServices            	       0x192ec8be0 __63-[FBSWorkspaceScenesClient willTerminateWithTransitionContext:]_block_invoke + 132
16  libdispatch.dylib             	       0x180a8f63c _dispatch_client_callout + 20
17  libdispatch.dylib             	       0x180a930f4 _dispatch_block_invoke_direct + 264
18  FrontBoardServices            	       0x192e84fa4 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 48
19  FrontBoardServices            	       0x192e843e4 -[FBSSerialQueue _targetQueue_performNextIfPossible] + 220
20  FrontBoardServices            	       0x192e889f4 -[FBSSerialQueue _performNextFromRunLoopSource] + 28
21  CoreFoundation                	       0x180e3f020 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
22  CoreFoundation                	       0x180e4fce0 __CFRunLoopDoSource0 + 208
23  CoreFoundation                	       0x180d8a054 __CFRunLoopDoSources0 + 376
24  CoreFoundation                	       0x180d8f7f4 __CFRunLoopRun + 820
25  CoreFoundation                	       0x180da33b8 CFRunLoopRunSpecific + 600
26  GraphicsServices              	       0x19cd7b38c GSEventRunModal + 164
27  UIKitCore                     	       0x1837400b8 -[UIApplication _run] + 1100
28  UIKitCore                     	       0x1834be1e8 UIApplicationMain + 2124
29  REDACTED                     	       0x10635a714 REDACTED + 534292 (AppDelegate.swift:384)
30  REDACTED                       	       0x1044cbe60 main + 32352 (<compiler-generated>:0)
31  dyld                          	       0x1047c5a24 start + 520

Thread 3 name:  ComScore-Thread
Thread 3:
0   libsystem_kernel.dylib        	       0x1b82ca204 __ulock_wait + 8
1   libdispatch.dylib             	       0x180a90030 _dlock_wait + 56
2   libdispatch.dylib             	       0x180a8fdd4 _dispatch_thread_event_wait_slow + 56
3   libdispatch.dylib             	       0x180a9eb78 __DISPATCH_WAIT_FOR_QUEUE__ + 364
4   libdispatch.dylib             	       0x180a9e720 _dispatch_sync_f_slow + 144
5   ComScore                      	       0x105c2a8cc +[SCORHelper appWindowResolution] + 228
6   ComScore                      	       0x105b8958c ComScore::EventManager::addPlatformLabels(ComScore::Event*) + 68
7   ComScore                      	       0x105b9e6d0 ComScore::EventManager::addLabels(ComScore::Event*, long long, ComScore::EventInfo const&, std::__1::shared_ptr<ComScore::Configuration>) + 1312
8   ComScore                      	       0x105b9cdc8 ComScore::EventManager::send(ComScore::Event*, long long, ComScore::EventInfo const&, std::__1::shared_ptr<ComScore::Configuration>) + 708
9   ComScore                      	       0x105b9ca9c ComScore::EventManager::sendHiddenEvent(long long, ComScore::EventInfo const&, std::__1::shared_ptr<ComScore::Configuration>) + 116
10  ComScore                      	       0x105bd9e48 std::__1::__function::__func<ComScore::Core::sendHiddenEvent(ComScore::EventInfo const&)::$_16, std::__1::allocator<ComScore::Core::sendHiddenEvent(ComScore::EventInfo const&)::$_16>, void (ComScore::Task*, std::__1::shared_ptr<ComScore::Configuration>)>::operator()(ComScore::Task*&&, std::__1::shared_ptr<ComScore::Configuration>&&) + 172
11  ComScore                      	       0x105bdb190 std::__1::__function::__func<ComScore::Core::newEventTask(std::__1::function<void (ComScore::Task*, std::__1::shared_ptr<ComScore::Configuration>)>)::$_28, std::__1::allocator<ComScore::Core::newEventTask(std::__1::function<void (ComScore::Task*, std::__1::shared_ptr<ComScore::Configuration>)>)::$_28>, void (ComScore::Task*)>::operator()(ComScore::Task*&&) + 536
12  ComScore                      	       0x105b97c74 ComScore::Task::run() + 44
13  ComScore                      	       0x105bd3140 ComScore::ContextTasksThread<ComScore::Core>::run() + 204
14  ComScore                      	       0x105c14bc4 ComScore::Thread::threadEntryPoint() + 104
15  ComScore                      	       0x105c18970 threadEntryProc + 32
16  libsystem_pthread.dylib       	       0x1f1d969a4 _pthread_start + 148
17  libsystem_pthread.dylib       	       0x1f1d95ea0 thread_start + 8

Thread 4 name:  ComScore-NetworkThread
Thread 4:
0   libsystem_kernel.dylib        	       0x1b82c9ff0 __psynch_cvwait + 8
1   libsystem_pthread.dylib       	       0x1f1d9d280 _pthread_cond_wait + 1272
2   ComScore                      	       0x105c142f8 ComScore::WaitableEvent::wait(int) const + 152
3   ComScore                      	       0x105bd31e8 ComScore::ContextTasksThread<ComScore::Core>::run() + 372
4   ComScore                      	       0x105c14bc4 ComScore::Thread::threadEntryPoint() + 104
5   ComScore                      	       0x105c18970 threadEntryProc + 32
6   libsystem_pthread.dylib       	       0x1f1d969a4 _pthread_start + 148
7   libsystem_pthread.dylib       	       0x1f1d95ea0 thread_start + 8

Thread 11 name:  ComScore-StreamingAnalytics-1
Thread 11:
0   libsystem_kernel.dylib        	       0x1b82c9ff0 __psynch_cvwait + 8
1   libsystem_pthread.dylib       	       0x1f1d9d280 _pthread_cond_wait + 1272
2   ComScore                      	       0x105c142f8 ComScore::WaitableEvent::wait(int) const + 152
3   ComScore                      	       0x105bdbdb8 ComScore::ContextTasksThread<ComScore::StreamingCore>::run() + 372
4   ComScore                      	       0x105c14bc4 ComScore::Thread::threadEntryPoint() + 104
5   ComScore                      	       0x105c18970 threadEntryProc + 32
6   libsystem_pthread.dylib       	       0x1f1d969a4 _pthread_start + 148
7   libsystem_pthread.dylib       	       0x1f1d95ea0 thread_start + 8

Thread 0 crashed with ARM Thread State (64-bit):
    x0: 0x0000000000000004   x1: 0x0000000000000000   x2: 0x0000000000000000   x3: 0x0000000000270853
    x4: 0x00000000000120a9   x5: 0x000000010736ced0   x6: 0x0000000000000000   x7: 0x0000000000000000
    x8: 0x000000010b529697   x9: 0x000000010b529690  x10: 0x000000010b529688  x11: 0x000000000026be9b
   x12: 0x0000000000000000  x13: 0x0000000000000002  x14: 0x0000000000000102  x15: 0x0000000000008800
   x16: 0x000000000000012d  x17: 0x00000001dce48870  x18: 0x00000001060ac5fc  x19: 0x000000010b529670
   x20: 0x0000000000000102  x21: 0x0000000000000000  x22: 0x000000010b529688  x23: 0x000000000026be9b
   x24: 0x000000010b529690  x25: 0x00000001dac7d000  x26: 0x000000000000001f  x27: 0x000000000000001e
   x28: 0x0000000000000002   fp: 0x000000016b93a250   lr: 0x00000001f1d973cc
    sp: 0x000000016b93a220   pc: 0x00000001b82ca6cc cpsr: 0x60000000
   far: 0x00000001817d339c  esr: 0x56000080  Address size fault

[xlith]

Hi @salling, Thanks for the detailed report. We are investigating the issue. We will let you know about the process.

[xlith]

It seems the problem occurs in the shutdown process. We are still investigating the issue, and it will take a little bit more time. While we try to fix it, we will keep this issue open let you know if anything happens. Luckily it doesn't affect user experience and, hopefully, we will provide an update soon.

Meanwhile, if you have any other data that you share with us we appreciate it. Any other crash logs (a full log would be better), code blocks, etc.

Thanks again for letting us know about the problem.

[xlith]

We could not recreate the crash. Could you share your implementation code, so we can try to recreate the environment that leads to the crash?

[mmcnabb2187]

We are also seeing this same crash come up in tvOS a fair amount, in our New Relic crash analyses.

[xlith]

Version 6.10.0 should resolve this issue. Thanks for the feedback and sorry for any inconvenience. Please feel free to reach us if you encounter any problems again.