这有点奇怪。
在我的代码中，我有这一行：
NSMutableArray *unresolvedPlayers = [NSMutableArray arrayWithCapacity:3];
这似乎是一个完全有效的路线。我用这个堆栈跟踪在这一行上崩溃了（我用xxxxxxxxx替换了我的应用名称）：
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0xc158f710
Triggered by Thread: 7
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0:
0 libsystem_kernel.dylib 0x3870d648 syscall_thread_switch + 8
1 libsystem_platform.dylib 0x3879a79a _os_lock_handoff_lock_slow + 74
2 libsystem_malloc.dylib 0x38748ece szone_malloc_should_clear + 50
3 libsystem_malloc.dylib 0x3874c444 malloc_zone_calloc + 92
4 libsystem_malloc.dylib 0x3874c3d2 calloc + 46
5 libobjc.A.dylib 0x380c8414 class_createInstance + 36
6 CoreFoundation 0x2a5773d0 __CFAllocateObject2 + 8
7 CoreFoundation 0x2a48c86a +[__NSArrayM __new:::::] + 38
8 CoreFoundation 0x2a48fd7c -[__NSPlaceholderArray initWithCapacity:] + 100
9 CoreFoundation 0x2a497e88 +[NSMutableArray arrayWithCapacity:] + 36
10 xxxxxxxxxx 0x001730f4 -[HostManager setHost:timestamp:] (HostManager.m:703)
11 xxxxxxxxxx 0x0016ff10 -[HostManager initSessionFromInvitation:] (HostManager.m:46)
12 xxxxxxxxxx 0x000ea68e -[NetworkController updateWithMatch:] (NetworkController.m:894)
13 xxxxxxxxxx 0x000ea418 __72-[NetworkController invitePlayersToMatch:playerGroup:completionHandler:]_block_invoke544 (NetworkController.m:844)
14 GameCenterFoundation 0x31263936 __72-[GKMatchmaker invitePlayersWithRequest:serverHosted:completionHandler:]_block_invoke601 + 42
15 libdispatch.dylib 0x38620420 _dispatch_call_block_and_release + 8
16 libdispatch.dylib 0x3862040c _dispatch_client_callout + 20
17 libdispatch.dylib 0x3862b1b0 _dispatch_main_queue_callback_4CF$VARIANT$mp + 708
18 CoreFoundation 0x2a53762c __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 4
19 CoreFoundation 0x2a535d4c __CFRunLoopRun + 1508
20 CoreFoundation 0x2a482b2c CFRunLoopRunSpecific + 472
21 CoreFoundation 0x2a48293e CFRunLoopRunInMode + 102
22 GraphicsServices 0x3183904c GSEventRunModal + 132
23 UIKit 0x2da786ec UIApplicationMain + 1436
24 xxxxxxxxxx 0x000503b2 main (main.m:16)
25 libdyld.dylib 0x3865baac start + 0
到目前为止，我的内存有多可能被破坏，分配新的NSMutableArray会导致这种情况发生？我甚至不知道从哪里开始调试这个。我不确定这是否容易重现。
作为旁注，这是在邀请附近的玩家参加实时GameCenter比赛时发生的。
编辑：我刚刚意识到这在线程7上崩溃了。这就是Thread 7的样子：
Thread 7 name: Dispatch queue: com.apple.root.default-qos
Thread 7 Crashed:
0 libobjc.A.dylib 0x380cbf66 objc_msgSend + 6
1 GameCenterFoundation 0x31285efc -[GKMatchmaker(Nearby) inviteAnyNearbyPlayersWithRequest:] + 960
2 GameCenterFoundation 0x312636a8 __72-[GKMatchmaker invitePlayersWithRequest:serverHosted:completionHandler:]_block_invoke + 256
3 GameCenterFoundation 0x3129ae92 __39-[GKDispatchGroup notifyOnQueue:block:]_block_invoke44 + 10
4 libdispatch.dylib 0x38620420 _dispatch_call_block_and_release + 8
5 libdispatch.dylib 0x3862c2d6 _dispatch_root_queue_drain + 846
6 libdispatch.dylib 0x3862d1f6 _dispatch_worker_thread3 + 102
7 libsystem_pthread.dylib 0x3879de22 _pthread_wqthread + 666
8 libsystem_pthread.dylib 0x3879db74 start_wqthread + 4
所以，这可能是GameCenter的一个错误。