Open Radar

 
Summary:
KVO crash notifying deallocated observer

Steps to Reproduce:
1. Create observer and observe object.property on Thread 1.
2. Mutate object.property on Thread 2.
3. Unobserve object.property and dealloc observer on Thread 1.
4. Repeat Steps 1-3.

1. Run Sample app attached.

Expected Results:
No crash.

Actual Results:
2014-02-04 15:56:00.469 FBKVOController[78158:1303] *** -[FBKVOController retain]: message sent to deallocated instance 0x6fd366fd0

(lldb) bt all
  thread #1: tid = 0x1ef872, 0x00000001022c3a1a libsystem_kernel.dylib`mach_msg_trap + 10, queue = 'com.apple.main-thread
    frame #0: 0x00000001022c3a1a libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x00000001022c2d18 libsystem_kernel.dylib`mach_msg + 64
    frame #2: 0x0000000101aa7255 CoreFoundation`__CFRunLoopServiceMachPort + 181
    frame #3: 0x0000000101aac7cf CoreFoundation`__CFRunLoopRun + 1199
    frame #4: 0x0000000101aabf33 CoreFoundation`CFRunLoopRunSpecific + 467
    frame #5: 0x0000000103c083a0 GraphicsServices`GSEventRunModal + 161
    frame #6: 0x000000010026e043 UIKit`UIApplicationMain + 1010
    frame #7: 0x0000000100002143 FBKVOController`main(argc=1, argv=0x00007fff5fbfec30) + 115 at main.m:16
    frame #8: 0x00000001021905fd libdyld.dylib`start + 1

  thread #2: tid = 0x1ef97c, 0x00000001022c8662 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager
    frame #0: 0x00000001022c8662 libsystem_kernel.dylib`kevent64 + 10
    frame #1: 0x0000000101ed5590 libdispatch.dylib`_dispatch_mgr_invoke + 239
    frame #2: 0x0000000101ed532d libdispatch.dylib`_dispatch_mgr_thread + 54

* thread #3: tid = 0x1ef97d, 0x0000000101af2fd4 CoreFoundation`___forwarding___ + 772, queue = 'com.apple.root.high-priority, stop reason = EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0)
    frame #0: 0x0000000101af2fd4 CoreFoundation`___forwarding___ + 772
    frame #1: 0x0000000101af2c48 CoreFoundation`_CF_forwarding_prep_0 + 120
    frame #2: 0x000000010120cf14 Foundation`NSKeyValuePushPendingNotificationPerThread + 363
    frame #3: 0x000000010120c836 Foundation`NSKeyValueWillChange + 453
    frame #4: 0x00000001011d00c3 Foundation`-[NSObject(NSKeyValueObserverNotification) willChangeValueForKey:] + 221
    frame #5: 0x00000001011a85e5 Foundation`_NSSetDoubleValueAndNotify + 105
    frame #6: 0x0000000100001bd3 FBKVOController`__24-[FBAppDelegate _stress]_block_invoke(.block_descriptor=<unavailable>) + 67 at FBAppDelegate.m:26
    frame #7: 0x0000000101ecf8c1 libdispatch.dylib`_dispatch_call_block_and_release + 12
    frame #8: 0x0000000101ee26fd libdispatch.dylib`_dispatch_client_callout + 8
    frame #9: 0x0000000101ed2b7d libdispatch.dylib`_dispatch_root_queue_drain + 362
    frame #10: 0x0000000101ed2d65 libdispatch.dylib`_dispatch_worker_thread2 + 40
    frame #11: 0x000000010228cef8 libsystem_pthread.dylib`_pthread_wqthread + 314
    frame #12: 0x000000010228ffb9 libsystem_pthread.dylib`start_wqthread + 13

  thread #4: tid = 0x1ef97e, 0x00000001022c3942 libsystem_kernel.dylib`_kernelrpc_mach_vm_allocate_trap + 10, queue = 'com.apple.root.high-priority
    frame #0: 0x00000001022c3942 libsystem_kernel.dylib`_kernelrpc_mach_vm_allocate_trap + 10
    frame #1: 0x00000001022c6783

Version:
iOS 7.0.3 (11B508)

Notes:


Configuration:
Xcode 5.0.2 (5A3005), OS X 10.9.1, MacBook Pro

Attachments:
'MacBook Pro.spx' and 'FBKVOController.zip' were successfully uploaded.

Attachment URL:
https://dl.dropboxusercontent.com/u/1898287/rdar/15985376/FBKVOController.zip