Crash in ASRunLoopQueue.mm line 270

[levi]

ASRunLoopQueue.mm line 270
-[ASRunLoopQueue processQueue]

Pinterest 1 (pinterest)
Issue #161748 (Level 1)

System: 9.3.3 (13G34) 9.3.3 (13G34) on Apple iPhone 6 (arm64)
Storage: disk 33% free (3951 MB) and memory 6% free (226 MB)
Orientation: device is portrait and UI is portrait
Session: 1011ce535ff34084b0ffef6ade2dc6ec_0d6cdab239624d62b83bce44eff6b0bd_0_v1
Timestamp: 2017-04-17T11:28:43.000Z

[Thread 0] Crashed: com.apple.main-thread
EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x000000001365d788
  0 libobjc.A.dylib                6453648272 objc_msgSend + 16
  1 Foundation                     6473769012 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKeys:count:maybeOldValuesDict:usingBlock:] + 356
  2 Foundation                     6473068480 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] + 64
  3 Foundation                     6473759544 _NSSetPointValueAndNotify + 284
  4 UIKit                          6552282908 -[UIScrollView(UIScrollViewInternal) _adjustContentOffsetIfNecessary] + 60
  5 UIKit                          6549898028 -[UIScrollView(UIScrollViewInternal) _stopScrollingNotify:pin:tramplingDragFlags:] + 460
  6 UIKit                          6549897504 -[UIScrollView removeFromSuperview] + 40
  7 UIKit                          6548949284 -[UIView dealloc] + 952
  8 Foundation                     6473427408 -[NSConcretePointerArray replacePointerAtIndex:withPointer:] + 192
> 9 Pinterest                      4302444428 -[ASRunLoopQueue processQueue] (ASRunLoopQueue.mm:270)
 10 CoreFoundation                 6463342376 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32
 11 CoreFoundation                 6463333580 __CFRunLoopDoObservers + 372
 12 CoreFoundation                 6463334652 __CFRunLoopRun + 928
 13 CoreFoundation                 6462458960 CFRunLoopRunSpecific + 384
 14 GraphicsServices               6488572040 GSEventRunModal + 180
 15 UIKit                          6549397640 UIApplicationMain + 204
 16 Pinterest                      4295564372 main (main.m:74)
 17 libdispatch.dylib              6457862328  + 0

[Thread 1] com.apple.libdispatch-manager
  0 libsystem_kernel.dylib         6459036888 kevent_qos + 8
  1 libdispatch.dylib              6457739224 _dispatch_mgr_invoke + 232
  2 libdispatch.dylib              6457669192 _dispatch_source_invoke + 50

[Thread 2]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 3] com.apple.NSURLConnectionLoader
  0 libsystem_kernel.dylib         6458920920 mach_msg_trap + 8
  1 libsystem_kernel.dylib         6458920532 mach_msg + 72
  2 CoreFoundation                 6463343712 __CFRunLoopServiceMachPort + 196
  3 CoreFoundation                 6463334756 __CFRunLoopRun + 1032
  4 CoreFoundation                 6462458960 CFRunLoopRunSpecific + 384
  5 CFNetwork                      6470327244 +[NSURLConnection(Loader) _resourceLoadLoop:] + 412
  6 Foundation                     6473956940 __NSThread__start__ + 1000
  7 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  8 libsystem_pthread.dylib        6459865740 _pthread_body + 154
  9 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 4] com.twitter.crashlytics.ios.MachExceptionServer
  0 Pinterest                      4306014612 CLSProcessRecordAllThreads + 1000568
  1 Pinterest                      4306014612 CLSProcessRecordAllThreads + 1000568
  2 Pinterest                      4306014288 CLSProcessRecordAllThreads + 1000244
  3 Pinterest                      4305950736 CLSHandler + 936692
  4 Pinterest                      4305930164 CLSMachExceptionServer + 916120
  5 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  6 libsystem_pthread.dylib        6459865740 _pthread_body + 154
  7 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 5]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 6] com.apple.CFSocket.private
  0 libsystem_kernel.dylib         6459032388 __select + 8
  1 CoreFoundation                 6463369672 __CFSocketManager + 648
  2 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  3 libsystem_pthread.dylib        6459865740 _pthread_body + 154
  4 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 7]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 8] AVAudioSession Notify Thread
  0 libsystem_kernel.dylib         6458920920 mach_msg_trap + 8
  1 libsystem_kernel.dylib         6458920532 mach_msg + 72
  2 CoreFoundation                 6463343712 __CFRunLoopServiceMachPort + 196
  3 CoreFoundation                 6463334756 __CFRunLoopRun + 1032
  4 CoreFoundation                 6462458960 CFRunLoopRunSpecific + 384
  5 libAVFAudio.dylib              6570957280 GenericRunLoopThread::Entry(void*) + 164
  6 libAVFAudio.dylib              6570780508 CAPThread::Entry(CAPThread*) + 84
  7 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  8 libsystem_pthread.dylib        6459865740 _pthread_body + 154
  9 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 9] ASDeallocQueue
  0 libsystem_kernel.dylib         6458920920 mach_msg_trap + 8
  1 libsystem_kernel.dylib         6458920532 mach_msg + 72
  2 CoreFoundation                 6463343712 __CFRunLoopServiceMachPort + 196
  3 CoreFoundation                 6463334756 __CFRunLoopRun + 1032
  4 CoreFoundation                 6462458960 CFRunLoopRunSpecific + 384
  5 CoreFoundation                 6462776228 CFRunLoopRun + 112
  6 Pinterest                      4302442152 -[ASDeallocQueue threadMain] (ASRunLoopQueue.mm:99)
  7 Foundation                     6473956940 __NSThread__start__ + 1000
  8 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  9 libsystem_pthread.dylib        6459865740 _pthread_body + 154
 10 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 10]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 11]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 12] Deadlock Detection Thread
  0 libsystem_kernel.dylib         6459032604 __semwait_signal + 8
  1 libsystem_c.dylib              6458102316 nanosleep + 212
  2 Foundation                     6473954040 +[NSThread sleepForTimeInterval:] + 136
  3 Pinterest                      4295972552 +[PIDeadlockDetector detectionThreadLoop:] (PIDeadlockDetector.m:134)
  4 Foundation                     6473956940 __NSThread__start__ + 1000
  5 libsystem_pthread.dylib        6459865896 _pthread_body + 156
  6 libsystem_pthread.dylib        6459865740 _pthread_body + 154
  7 libsystem_pthread.dylib        6459854888 thread_start + 4

[Thread 13]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 14]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 15]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 16]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Thread 17]
  0 libsystem_kernel.dylib         6459034440 __workq_kernreturn + 8
  1 libsystem_pthread.dylib        6459856176 _pthread_wqthread + 1284
  2 libsystem_pthread.dylib        6459854880 start_wqthread + 4

[Adlai-Holler]

@levi It looks like someone is using KVO to observe UIScrollView.contentOffset and the scroll view is trying to send KVO notifications from inside dealloc and messaging a dangling pointer. Looking into the code a bit, it seems likely that since the object argument to FBKVOController block is strong, the mechanism is trying to retain the scroll view, which is prohibited from within dealloc.

• Using KVO to observe UIKit properties is not supported.
• If you have to keep doing this, ensure that the KVO observation is torn down before the scroll view enters dealloc. One workaround is to pass retainObserved:YES into FBKVOController.

Cheers!