Unknown exception and crash <p>My application crashes when I try to scroll the tableview very fast or reload the data from remote. Everything seems to be working fine, when I let the remote fetch happen first and then scroll the tableview. I have no idea what the crash log below means. It just works fine sometimes and crashes sometime. </p> <pre><code>Incident Identifier: 710A120C-97E3-45C8-A7B2-E6A7BD98BC1A CrashReporter Key: 8bd54d8428128b9e6b8c04d59b86c40cccf33457 Hardware Model: iPhone5,2 Process: MyApp [5294] Path: /var/mobile/Applications/B6ED5B19-B8D7-4146-90A2-F709AE35292F/MyApp.app/MyApp Identifier: MyApp Version: ??? (???) Code Type: ARM (Native) Parent Process: launchd [1] Date/Time: 2013-02-26 16:45:27.693 +0200 OS Version: iOS 6.1.2 (10B146) Report Version: 104 Exception Type: EXC_CRASH (SIGSEGV) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 1 Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0: 0 libobjc.A.dylib 0x3c3f658a _cache_getImp + 10 1 libobjc.A.dylib 0x3c3f6fa0 lookUpMethod + 24 2 libobjc.A.dylib 0x3c3f81e2 class_respondsToSelector + 26 3 CoreFoundation 0x3470a750 objectIsKindOfClass + 32 4 CoreFoundation 0x3470a49c __handleUncaughtException + 64 5 libobjc.A.dylib 0x3c3fba46 _objc_terminate() + 126 6 libc++abi.dylib 0x3be48118 safe_handler_caller(void (*)()) + 76 7 libc++abi.dylib 0x3be481b0 std::terminate() + 16 8 libc++abi.dylib 0x3be49626 __cxa_rethrow + 90 9 libobjc.A.dylib 0x3c3fb9b0 objc_exception_rethrow + 8 10 CoreFoundation 0x3465129c CFRunLoopRunSpecific + 452 11 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 12 GraphicsServices 0x3822f336 GSEventRunModal + 70 13 UIKit 0x3656d2b4 UIApplicationMain + 1116 14 MyApp 0x000910a2 0x44000 + 315554 15 MyApp 0x0004668c 0x44000 + 9868 Thread 1 name: Dispatch queue: com.apple.libdispatch-manager Thread 1 Crashed: 0 libsystem_kernel.dylib 0x3c8df5d0 kevent64 + 24 1 libdispatch.dylib 0x3c81ad22 _dispatch_mgr_invoke + 806 2 libdispatch.dylib 0x3c816374 _dispatch_mgr_thread + 32 Thread 2 name: WebThread Thread 2: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 6 WebCore 0x3a650390 RunWebThread(void*) + 440 7 libsystem_c.dylib 0x3c8480de _pthread_start + 306 8 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 3 name: com.apple.NSURLConnectionLoader Thread 3: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 6 Foundation 0x34f9e888 +[NSURLConnection(Loader) _resourceLoadLoop:] + 304 7 Foundation 0x3502222c __NSThread__main__ + 968 8 libsystem_c.dylib 0x3c8480de _pthread_start + 306 9 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 4: 0 libsystem_kernel.dylib 0x3c8efd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3c83dad6 _pthread_workq_return + 14 2 libsystem_c.dylib 0x3c83d7f2 _pthread_wqthread + 362 3 libsystem_c.dylib 0x3c83d680 start_wqthread + 4 Thread 5: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 6 Foundation 0x34f755be -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 250 7 Foundation 0x35018c40 -[NSRunLoop(NSRunLoop) run] + 76 8 MyApp 0x0016b900 0x44000 + 1210624 9 Foundation 0x3502222c __NSThread__main__ + 968 10 libsystem_c.dylib 0x3c8480de _pthread_start + 306 11 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 6: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 6 Foundation 0x34f755be -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 250 7 Foundation 0x35018c40 -[NSRunLoop(NSRunLoop) run] + 76 8 MyApp 0x000e63d0 0x44000 + 664528 9 Foundation 0x3502222c __NSThread__main__ + 968 10 libsystem_c.dylib 0x3c8480de _pthread_start + 306 11 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 7 name: com.apple.CFSocket.private Thread 7: 0 libsystem_kernel.dylib 0x3c8ef594 __select + 20 1 CoreFoundation 0x346e3474 __CFSocketManager + 676 2 libsystem_c.dylib 0x3c8480de _pthread_start + 306 3 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 8: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346afc46 CFRunLoopRun + 94 6 MyApp 0x00115d7e 0x44000 + 859518 7 Foundation 0x3502222c __NSThread__main__ + 968 8 libsystem_c.dylib 0x3c8480de _pthread_start + 306 9 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 9: 0 libsystem_kernel.dylib 0x3c8efd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3c83dad6 _pthread_workq_return + 14 2 libsystem_c.dylib 0x3c83d7f2 _pthread_wqthread + 362 3 libsystem_c.dylib 0x3c83d680 start_wqthread + 4 Thread 10: 0 libsystem_kernel.dylib 0x3c8efd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3c83dad6 _pthread_workq_return + 14 2 libsystem_c.dylib 0x3c83d7f2 _pthread_wqthread + 362 3 libsystem_c.dylib 0x3c83d680 start_wqthread + 4 Thread 11 name: JavaScriptCore::BlockFree Thread 11: 0 libsystem_kernel.dylib 0x3c8ef08c __psynch_cvwait + 24 1 libsystem_c.dylib 0x3c840afc _pthread_cond_wait + 644 2 libsystem_c.dylib 0x3c840870 pthread_cond_timedwait + 40 3 JavaScriptCore 0x38625df6 WTF::ThreadCondition::timedWait(WTF::Mutex&amp;, double) + 102 4 JavaScriptCore 0x38738532 JSC::BlockAllocator::blockFreeingThreadMain() + 78 5 JavaScriptCore 0x3874b030 WTF::wtfThreadEntryPoint(void*) + 12 6 libsystem_c.dylib 0x3c8480de _pthread_start + 306 7 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 12 name: JavaScriptCore::Marking Thread 12: 0 libsystem_kernel.dylib 0x3c8ef08c __psynch_cvwait + 24 1 libsystem_c.dylib 0x3c840afc _pthread_cond_wait + 644 2 libsystem_c.dylib 0x3c84acf8 pthread_cond_wait + 36 3 JavaScriptCore 0x386cb6dc JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode) + 140 4 JavaScriptCore 0x386cb620 JSC::MarkStackThreadSharedData::markingThreadMain() + 140 5 JavaScriptCore 0x3874b030 WTF::wtfThreadEntryPoint(void*) + 12 6 libsystem_c.dylib 0x3c8480de _pthread_start + 306 7 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 13 name: WebCore: CFNetwork Loader Thread 13: 0 libsystem_kernel.dylib 0x3c8dee30 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x3c8defd0 mach_msg + 48 2 CoreFoundation 0x346df2b6 __CFRunLoopServiceMachPort + 126 3 CoreFoundation 0x346de02c __CFRunLoopRun + 900 4 CoreFoundation 0x34651238 CFRunLoopRunSpecific + 352 5 CoreFoundation 0x346510c4 CFRunLoopRunInMode + 100 6 WebCore 0x3a6eaccc WebCore::runLoaderThread(void*) + 140 7 JavaScriptCore 0x3874b030 WTF::wtfThreadEntryPoint(void*) + 12 8 libsystem_c.dylib 0x3c8480de _pthread_start + 306 9 libsystem_c.dylib 0x3c847fa4 thread_start + 4 Thread 14: 0 libsystem_kernel.dylib 0x3c8efd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3c83dad6 _pthread_workq_return + 14 2 libsystem_c.dylib 0x3c83d7f2 _pthread_wqthread + 362 3 libsystem_c.dylib 0x3c83d680 start_wqthread + 4 Thread 1 crashed with ARM Thread State (32-bit): r0: 0x00000004 r1: 0x00000000 r2: 0x00000000 r3: 0x0042c714 r4: 0x00000001 r5: 0x00000000 r6: 0x0042c744 r7: 0x0042c764 r8: 0x00000000 r9: 0x0042c6c8 r10: 0x3e3a2188 r11: 0x00000002 ip: 0x00000171 sp: 0x0042c6d0 lr: 0x3c81ad27 pc: 0x3c8df5d0 cpsr: 0x60000010 </code></pre> <p>I would be really happy if anybody could explain me what this crash log could relate to and how I could solve it. Many many thanks to all those who are willing to help others.</p>