Garnage CollectorがオンのときにWebビューがクラッシュする（オフのときにクラッシュしない）非常に特殊なWebページがあります。
再現が簡単：ドキュメントベースのアプリケーションを作成し、Webビューをドロップして、次の行（おそらくボタン）を作成します。
- (void)connectSearch:(id)sender
{
[[webView mainFrame] loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://apple.com"]]];
}
このシナリオは、Appleが新しいiPadを宣伝している間だけ有効だと思います。ページの下部には、視聴できる2つのビデオがあります。右の方をクリックしてください。再生中に、左上の[閉じる]ボタン（リンク）をクリックします。これにより、＃SwapViewPreviousSelectionが送信されます。これで、クラッシュします。
ガベージコレクターについて学習しているところですが、収集されるべきではないものが収集されているのではないかと思います。
ガベージコレクターをオフにする以外に、クラッシュを防ぐことができるアイデアはありますか？
ありがとうございました。
これが私が得るものです：
Identifier: com.yourcompany.wb
Version: 1.0 (1)
Code Type: X86-64 (Native)
Parent Process: launchd [163]
Date/Time: 2010-02-15 12:26:31.069 -0500
OS Version: Mac OS X 10.6.2 (10C540)
Report Version: 6
Interval Since Last Report: 432447 sec
Crashes Since Last Report: 7
Per-App Interval Since Last Report: 2938 sec
Per-App Crashes Since Last Report: 5
Anonymous UUID: CC123A77-1407-444A-9081-8A2B7C15C2B6
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Application Specific Information:
objc[70635]: garbage collection is ON
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 com.apple.CoreFoundation 0x00007fff82e0a788 CFRetain + 200
1 com.apple.QuartzCore 0x00007fff81677a98 -[CALayer setSublayers:] + 486
2 com.apple.WebCore 0x00007fff87c792a1 WebCore::GraphicsLayerCA::updateSublayerList() + 433
3 com.apple.WebCore 0x00007fff87c7ebd8 WebCore::GraphicsLayerCA::commitLayerChanges() + 840
4 com.apple.WebCore 0x00007fff87c7ed05 WebCore::GraphicsLayerCA::recursiveCommitChanges() + 21
5 com.apple.WebCore 0x00007fff87c7ed31 WebCore::GraphicsLayerCA::recursiveCommitChanges() + 65
6 com.apple.WebCore 0x00007fff87705296 WebCore::FrameView::paintContents(WebCore::GraphicsContext*, WebCore::IntRect const&) + 390
7 com.apple.WebKit 0x00007fff81b3d205 -[WebFrame(WebInternal) _drawRect:contentsOnly:] + 149
8 com.apple.WebKit 0x00007fff81b3ce77 -[WebHTMLView drawSingleRect:] + 455
9 com.apple.WebKit 0x00007fff81b3cc16 -[WebHTMLView drawRect:] + 566
10 com.apple.AppKit 0x00007fff8597b05e -[NSView _drawRect:clip:] + 3566
11 com.apple.AppKit 0x00007fff85978834 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 2112
12 com.apple.WebKit 0x00007fff81b3dd6b -[WebHTMLView(WebPrivate) _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 299
13 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
14 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
15 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
16 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
17 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
18 com.apple.AppKit 0x00007fff859791bf -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 4555
19 com.apple.AppKit 0x00007fff85977e17 -[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 254
20 com.apple.AppKit 0x00007fff859746bf -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] + 2683
21 com.apple.AppKit 0x00007fff858edf37 -[NSView displayIfNeeded] + 969
22 com.apple.AppKit 0x00007fff858e8dde _handleWindowNeedsDisplay + 678
23 com.apple.CoreFoundation 0x00007fff82e74427 __CFRunLoopDoObservers + 519
24 com.apple.CoreFoundation 0x00007fff82e502d4 __CFRunLoopRun + 468
25 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
26 com.apple.HIToolbox 0x00007fff88192a4e RunCurrentEventLoopInMode + 333
27 com.apple.HIToolbox 0x00007fff881927b1 ReceiveNextEventCommon + 148
28 com.apple.HIToolbox 0x00007fff8819270c BlockUntilNextEventMatchingListInMode + 59
29 com.apple.AppKit 0x00007fff858be1f2 _DPSNextEvent + 708
30 com.apple.AppKit 0x00007fff858bdb41 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155
31 com.apple.AppKit 0x00007fff85883747 -[NSApplication run] + 395
32 com.apple.AppKit 0x00007fff8587c468 NSApplicationMain + 364
33 com.yourcompany.wb 0x0000000100001c86 main + 33 (main.m:14)
34 com.yourcompany.wb 0x0000000100001a44 start + 52
Thread 1: Dispatch queue: com.apple.libdispatch-manager
0 libSystem.B.dylib 0x00007fff8874bbba kevent + 10
1 libSystem.B.dylib 0x00007fff8874da85 _dispatch_mgr_invoke + 154
2 libSystem.B.dylib 0x00007fff8874d75c _dispatch_queue_invoke + 185
3 libSystem.B.dylib 0x00007fff8874d286 _dispatch_worker_thread2 + 244
4 libSystem.B.dylib 0x00007fff8874cbb8 _pthread_wqthread + 353
5 libSystem.B.dylib 0x00007fff8874ca55 start_wqthread + 13
Thread 2: JavaScriptCore: FastMalloc scavenger
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.JavaScriptCore 0x00007fff80ae62b3 WTF::TCMalloc_PageHeap::scavengerThread() + 515
3 com.apple.JavaScriptCore 0x00007fff80ae62f9 WTF::TCMalloc_PageHeap::runScavengerThread(void*) + 9
4 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
5 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 3:
0 libSystem.B.dylib 0x00007fff8874c9da __workq_kernreturn + 10
1 libSystem.B.dylib 0x00007fff8874cdec _pthread_wqthread + 917
2 libSystem.B.dylib 0x00007fff8874ca55 start_wqthread + 13
Thread 4:
0 libSystem.B.dylib 0x00007fff88732e3a mach_msg_trap + 10
1 libSystem.B.dylib 0x00007fff887334ad mach_msg + 59
2 com.apple.CoreFoundation 0x00007fff82e507a2 __CFRunLoopRun + 1698
3 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
4 com.apple.Foundation 0x00007fff800de4cf +[NSURLConnection(NSURLConnectionReallyInternal) _resourceLoadLoop:] + 297
5 com.apple.Foundation 0x00007fff8005ee99 __NSThread__main__ + 1429
6 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
7 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 5:
0 libSystem.B.dylib 0x00007fff887769e2 select$DARWIN_EXTSN + 10
1 com.apple.CoreFoundation 0x00007fff82e72242 __CFSocketManager + 818
2 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
3 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 6:
0 libSystem.B.dylib 0x00007fff8874c9da __workq_kernreturn + 10
1 libSystem.B.dylib 0x00007fff8874cdec _pthread_wqthread + 917
2 libSystem.B.dylib 0x00007fff8874ca55 start_wqthread + 13
Thread 7:
0 libSystem.B.dylib 0x00007fff8873d426 read + 10
1 com.apple.CoreFoundation 0x00007fff82eb1ae0 __CFSocketRead + 544
2 com.apple.CFNetwork 0x00007fff88bba667 __CFSocketReadWithError(__CFSocket*, unsigned char*, long, CFStreamError*) + 35
3 com.apple.CFNetwork 0x00007fff88bba397 SocketStream::read(__CFReadStream*, unsigned char*, long, CFStreamError*, unsigned char*) + 699
4 com.apple.CoreFoundation 0x00007fff82e3ffac CFReadStreamRead + 540
5 com.apple.CFNetwork 0x00007fff88bd3dc1 HTTPReadFilter::doPlainRead(unsigned char*, long, CFStreamError*, unsigned char*) + 307
6 com.apple.CFNetwork 0x00007fff88bd3c59 HTTPReadFilter::streamRead(__CFReadStream*, unsigned char*, long, CFStreamError*, unsigned char*) + 469
7 com.apple.CoreFoundation 0x00007fff82e3ffac CFReadStreamRead + 540
8 com.apple.CFNetwork 0x00007fff88bd39e6 HTTPNetStreamInfo::streamRead(__CFReadStream*, unsigned char*, long, CFStreamError*, unsigned char*) + 562
9 com.apple.CoreFoundation 0x00007fff82e3ffac CFReadStreamRead + 540
10 com.apple.CFNetwork 0x00007fff88c23892 HTTPReadStream::streamRead(__CFReadStream*, unsigned char*, long, CFStreamError*, unsigned char*) + 82
11 com.apple.CoreFoundation 0x00007fff82e3ffac CFReadStreamRead + 540
12 com.apple.MediaToolbox 0x00007fff86b59a6f FigCFHTTPReadResponse + 855
13 com.apple.CoreFoundation 0x00007fff82eb1503 _signalEventSync + 115
14 com.apple.CoreFoundation 0x00007fff82eb1474 _cfstream_solo_signalEventSync + 116
15 com.apple.CFNetwork 0x00007fff88c228fd HTTPReadStream::streamEvent(unsigned long) + 163
16 com.apple.CoreFoundation 0x00007fff82eb1503 _signalEventSync + 115
17 com.apple.CoreFoundation 0x00007fff82eb1474 _cfstream_solo_signalEventSync + 116
18 com.apple.CoreFoundation 0x00007fff82e52271 __CFRunLoopDoSources0 + 1361
19 com.apple.CoreFoundation 0x00007fff82e50469 __CFRunLoopRun + 873
20 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
21 com.apple.CoreFoundation 0x00007fff82e4f9b6 CFRunLoopRun + 70
22 com.apple.CoreMedia 0x00007fff803d4702 FigThreadGlobalNetworkBufferingRunloop + 119
23 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
24 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 8:
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.CoreMedia 0x00007fff803d5947 WaitOnCondition + 14
3 com.apple.CoreMedia 0x00007fff803d5b13 FigSemaphoreWaitRelative + 167
4 com.apple.MediaToolbox 0x00007fff86aee8c7 FigAIORequestThread + 398
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 9:
0 libSystem.B.dylib 0x00007fff8874c9da __workq_kernreturn + 10
1 libSystem.B.dylib 0x00007fff8874cdec _pthread_wqthread + 917
2 libSystem.B.dylib 0x00007fff8874ca55 start_wqthread + 13
Thread 10:
0 libSystem.B.dylib 0x00007fff88732e3a mach_msg_trap + 10
1 libSystem.B.dylib 0x00007fff887334ad mach_msg + 59
2 com.apple.CoreFoundation 0x00007fff82e507a2 __CFRunLoopRun + 1698
3 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
4 com.apple.CoreFoundation 0x00007fff82e4f9b6 CFRunLoopRun + 70
5 com.apple.QTKit 0x00007fff830d0c49 QTFigVisualContextImageProviderWorkThread + 342
6 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
7 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 11:
0 libSystem.B.dylib 0x00007fff88732e3a mach_msg_trap + 10
1 libSystem.B.dylib 0x00007fff887334ad mach_msg + 59
2 com.apple.CoreFoundation 0x00007fff82e507a2 __CFRunLoopRun + 1698
3 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
4 ....audio.toolbox.AudioToolbox 0x00007fff8416267a GenericRunLoopThread::RunLoop() + 42
5 ....audio.toolbox.AudioToolbox 0x00007fff841629f0 GenericRunLoopThread::Run() + 140
6 ....audio.toolbox.AudioToolbox 0x00007fff8412ded5 CAPThread::Entry(CAPThread*) + 67
7 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
8 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 12:
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.CoreMedia 0x00007fff803d5947 WaitOnCondition + 14
3 com.apple.CoreMedia 0x00007fff803d5b13 FigSemaphoreWaitRelative + 167
4 com.apple.MediaToolbox 0x00007fff86afd4dd faq_EnqueueSourceDataThread + 44
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 13:
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.CoreMedia 0x00007fff803d5947 WaitOnCondition + 14
3 com.apple.CoreMedia 0x00007fff803d5b13 FigSemaphoreWaitRelative + 167
4 com.apple.MediaToolbox 0x00007fff86b9b03b activitySchedulerOnThread + 69
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 14:
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.CoreMedia 0x00007fff803d5947 WaitOnCondition + 14
3 com.apple.CoreMedia 0x00007fff803d5b13 FigSemaphoreWaitRelative + 167
4 com.apple.MediaToolbox 0x00007fff86b26d49 audioMentorThread + 6000
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 15:
0 libSystem.B.dylib 0x00007fff8876d9ee __semwait_signal + 10
1 libSystem.B.dylib 0x00007fff887717f1 _pthread_cond_wait + 1286
2 com.apple.CoreMedia 0x00007fff803d5947 WaitOnCondition + 14
3 com.apple.CoreMedia 0x00007fff803d5b13 FigSemaphoreWaitRelative + 167
4 com.apple.MediaToolbox 0x00007fff86b3003a videoMentorThread + 5700
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 16:
0 libSystem.B.dylib 0x00007fff88732e3a mach_msg_trap + 10
1 libSystem.B.dylib 0x00007fff887334ad mach_msg + 59
2 com.apple.CoreFoundation 0x00007fff82e507a2 __CFRunLoopRun + 1698
3 com.apple.CoreFoundation 0x00007fff82e4fc2f CFRunLoopRunSpecific + 575
4 com.apple.CoreFoundation 0x00007fff82e4f9b6 CFRunLoopRun + 70
5 com.apple.QTKit 0x00007fff830cfad4 QTCALayerRendererPendingQWorkLoop + 534
6 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
7 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 17:
0 libSystem.B.dylib 0x00007fff88732e76 semaphore_wait_trap + 10
1 com.apple.VideoToolbox 0x00007fff80487f25 JVTLib_100988 + 11
2 com.apple.VideoToolbox 0x00007fff804d61d8 JVTLib_101021(void*) + 60
3 com.apple.VideoToolbox 0x00007fff804882f4 JVTLib_100971 + 552
4 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
5 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 18:
0 libSystem.B.dylib 0x00007fff88732e76 semaphore_wait_trap + 10
1 com.apple.VideoToolbox 0x00007fff80487f25 JVTLib_100988 + 11
2 com.apple.VideoToolbox 0x00007fff804d61d8 JVTLib_101021(void*) + 60
3 com.apple.VideoToolbox 0x00007fff804882f4 JVTLib_100971 + 552
4 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
5 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 19:
0 libSystem.B.dylib 0x00007fff88732e9a semaphore_timedwait_signal_trap + 10
1 libSystem.B.dylib 0x00007fff887716e2 _pthread_cond_wait + 1015
2 com.apple.CoreVideo 0x00007fff83d2988c CVDisplayLink::waitUntil(unsigned long long) + 252
3 com.apple.CoreVideo 0x00007fff83d28d91 CVDisplayLink::runIOThread() + 619
4 com.apple.CoreVideo 0x00007fff83d28aeb startIOThread(void*) + 139
5 libSystem.B.dylib 0x00007fff8876bf8e _pthread_start + 331
6 libSystem.B.dylib 0x00007fff8876be41 thread_start + 13
Thread 0 crashed with X86 Thread State (64-bit):
rax: 0x0000000000000000 rbx: 0x0000000000000000 rcx: 0x0000000000000000 rdx: 0x0000000000000018
rdi: 0x0000000000000000 rsi: 0x000000020070f7d8 rbp: 0x00007fff5fbfbcf0 rsp: 0x00007fff5fbfbce0
r8: 0x00000001010e48d0 r9: 0x000000000000f740 r10: 0x00000001010e42f0 r11: 0x00007fff87d9ca50
r12: 0x0000000101238600 r13: 0x0000000000000000 r14: 0x000000020070f7c0 r15: 0x0000000000000000
rip: 0x00007fff82e0a788 rfl: 0x0000000000000246 cr2: 0x00007fff702c13c8