IOS NSURLConnection _resourceLoadLoop crash

Question

I met a strange problem

I am using NSURLConnection to execute a URL request

it works great on a simulator

but it crashes on ipad2 5.0

I tried iPad1 5.01, ipad2 4.33, ipad2 5.01, it worked fine

just crashing on ipad2 5.0

I'm not sure what the problem is

Something seems to be wrong with

[NSURLConnection (Loader) _resourceLoadLoop:]

I thought that the NSURLConnection delegate could be destroyed before the NSURLConnection does this.

so i keep the delegate but fail anyway

Does anyone know what might cause this problem?

alarm log:

Date/Time: 2012-02-14 23:31:47.416 +0800 OS Version: iPhone OS 5.0 (9A334) Report Version: 104 Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x000049de Highlighted Thread: 3 Thread 0 name: Dispatch queue: com.apple.libdispatch-manager Thread 0: 0 libsystem_kernel.dylib 0x31e973b4 kevent + 24 1 libdispatch.dylib 0x316a6f74 _dispatch_mgr_invoke + 708 2 libdispatch.dylib 0x316a6c92 _dispatch_mgr_thread + 30 Thread 1: 0 libsystem_kernel.dylib 0x31ea7cd4 __workq_kernreturn + 8 1 libsystem_c.dylib 0x30d2730a _pthread_wqthread + 610 2 libsystem_c.dylib 0x30d2709c start_wqthread + 0 Thread 2 name: WebThread Thread 2: 0 libsystem_kernel.dylib 0x31e97010 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x31e97206 mach_msg + 50 2 CoreFoundation 0x371c441c __CFRunLoopServiceMachPort + 120 3 CoreFoundation 0x371c3154 __CFRunLoopRun + 876 4 CoreFoundation 0x371464d6 CFRunLoopRunSpecific + 294 5 CoreFoundation 0x3714639e CFRunLoopRunInMode + 98 6 WebCore 0x347ac128 _ZL12RunWebThreadPv + 396 7 libsystem_c.dylib 0x30d2cc16 _pthread_start + 314 8 libsystem_c.dylib 0x30d2cad0 thread_start + 0 Thread 3 name: com.apple.NSURLConnectionLoader Thread 3: 0 libsystem_kernel.dylib 0x31e97010 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x31e97206 mach_msg + 50 2 CoreFoundation 0x371c441c __CFRunLoopServiceMachPort + 120 3 CoreFoundation 0x371c3154 __CFRunLoopRun + 876 4 CoreFoundation 0x371464d6 CFRunLoopRunSpecific + 294 5 CoreFoundation 0x3714639e CFRunLoopRunInMode + 98 6 Foundation 0x31ab0bc2 +[NSURLConnection(Loader) _resourceLoadLoop:] + 302 7 Foundation 0x31ab0a8a -[NSThread main] + 66 8 Foundation 0x31b4459a __NSThread__main__ + 1042 9 libsystem_c.dylib 0x30d2cc16 _pthread_start + 314 10 libsystem_c.dylib 0x30d2cad0 thread_start + 0 Thread 4 name: WebCore: CFNetwork Loader Thread 4: 0 libsystem_kernel.dylib 0x31e97010 mach_msg_trap + 20 1 libsystem_kernel.dylib 0x31e97206 mach_msg + 50 2 CoreFoundation 0x371c441c __CFRunLoopServiceMachPort + 120 3 CoreFoundation 0x371c3154 __CFRunLoopRun + 876 4 CoreFoundation 0x371464d6 CFRunLoopRunSpecific + 294 5 CoreFoundation 0x3714639e CFRunLoopRunInMode + 98 6 WebCore 0x347d569e _ZN7WebCoreL15runLoaderThreadEPv + 122 7 libsystem_c.dylib 0x30d2cc16 _pthread_start + 314 8 libsystem_c.dylib 0x30d2cad0 thread_start + 0 Thread 5 name: com.apple.CFSocket.private Thread 5: 0 libsystem_kernel.dylib 0x31ea7570 __select + 20 1 CoreFoundation 0x371c866a __CFSocketManager + 726 2 libsystem_c.dylib 0x30d2cc16 _pthread_start + 314 3 libsystem_c.dylib 0x30d2cad0 thread_start + 0 Thread 6 name: WebCore: LocalStorage Thread 6: 0 libsystem_kernel.dylib 0x31ea7068 __psynch_cvwait + 24 1 libsystem_c.dylib 0x30d2cf2e _pthread_cond_wait + 634 2 libsystem_c.dylib 0x30d2ccaa pthread_cond_wait + 34 3 JavaScriptCore 0x3382040e WTF::ThreadCondition::timedWait(WTF::Mutex&, double) + 54 4 WebCore 0x3490b494 WTF::PassOwnPtr<WebCore::LocalStorageTask> WTF::MessageQueue<WebCore::LocalStorageTask>::waitForMessageFilteredWithTimeout<bool ()(WebCore::LocalStorageTask*)>(WTF::MessageQueueWaitResult&, bool (&)(WebCore::LocalStorageTask*), double) + 52 5 WebCore 0x3490b44a WebCore::LocalStorageThread::threadEntryPointCallback(void*) + 106 6 libsystem_c.dylib 0x30d2cc16 _pthread_start + 314 7 libsystem_c.dylib 0x30d2cad0 thread_start + 0 Unknown thread crashed with ARM Thread State: r0: 0x0000499a r1: 0x00000000 r2: 0x35fca80d r3: 0x00000000 r4: 0x0014bf50 r5: 0x3e4ce540 r6: 0x00115030 r7: 0x00000000 r8: 0x001d5a60 r9: 0x000000fb r10: 0x2fe5a688 r11: 0x305b1913 ip: 0x00067a2d sp: 0x2fe5a688 lr: 0x00067a49 pc: 0x30878f4e cpsr: 0x60000030 

Answer 1

When the crash logs say “Dedicated stream:”, it could be another stream. He is not sure.

It seems that all threads except thread 0 (main thread) stop waiting or trapping. Since the thread-zero is the only one that appears active, it is a real source of failure.

Since thread 0 has main () or UIApplication at the bottom, the stack is probably corrupt or it is in some system functions that use a non-standard way to create stack frames.