I have an iOS application built using a UIWebView and HTML5 websockets. The app experiences seemingly random crashes. It has occurred while a user is interacting with it and during longevity tests where no interaction between user and app occurs.
The crash logs all have the following:
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x00000000
and the thread logs contain:
Thread XX name: WebCore: Worker
Thread XX Crashed:
0 WebCore 0x36c8c7a0 WebCore::UserGestureIndicator::processingUserGesture() + 20
1 WebCore 0x36d7070a WebCore::DOMTimer::DOMTimer(WebCore::ScriptExecutionContext*, WTF::PassOwnPtr<WebCore::ScheduledAction>, int, bool) + 74
2 WebCore 0x36d70616 WebCore::DOMTimer::install(WebCore::ScriptExecutionContext*, WTF::PassOwnPtr<WebCore::ScheduledAction>, int, bool) + 46
3 WebCore 0x3753ae7e WebCore::WorkerContext::setTimeout(WTF::PassOwnPtr<WebCore::ScheduledAction>, int) + 30
4 WebCore 0x3731ac02 WebCore::JSWorkerContext::setTimeout(JSC::ExecState*) + 194
5 WebCore 0x37318ff6 WebCore::jsWorkerContextPrototypeFunctionSetTimeout(JSC::ExecState*) + 110
6 JavaScriptCore 0x2fa9a1d8 llint_native_call_trampoline + 62
7 JavaScriptCore 0x2faa355a JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) + 66
8 WebCore 0x36db0b16 WebCore::JSEventListener::handleEvent(WebCore::ScriptExecutionContext*, WebCore::Event*) + 558
9 WebCore 0x36d6ebba WebCore::EventTarget::fireEventListeners(WebCore::Event*, WebCore::EventTargetData*, WTF::Vector<WebCore::RegisteredEventListener, 1ul, WTF::CrashOnOverflow>&) + 482
10 WebCore 0x36c6da2a WebCore::EventTarget::fireEventListeners(WebCore::Event*) + 174
11 WebCore 0x36e28824 WebCore::EventTarget::dispatchEvent(WTF::PassRefPtr<WebCore::Event>) + 60
12 WebCore 0x3753e596 WebCore::MessageWorkerContextTask::performTask(WebCore::ScriptExecutionContext*) + 222
13 WebCore 0x3753ec6e WebCore::WorkerRunLoop::runInMode(WebCore::WorkerContext*, WebCore::ModePredicate const&, WebCore::WorkerRunLoop::WaitMode) + 158
14 WebCore 0x3753eb94 WebCore::WorkerRunLoop::run(WebCore::WorkerContext*) + 60
15 WebCore 0x37540d64 WebCore::WorkerThread::workerThread() + 432
16 JavaScriptCore 0x2fa4ba68 WTF::wtfThreadEntryPoint(void*) + 12
17 libsystem_pthread.dylib 0x397b6c5a _pthread_body + 138
18 libsystem_pthread.dylib 0x397b6bca _pthread_start + 98
19 libsystem_pthread.dylib 0x397b4ccc thread_start + 4
I managed to catch the exception on throw, and from what I can tell it looks to be a framework bug. See attached screenshot.
Most of what I've read seem to indicate that the web view is being dealloced prior to a delegate firing, but nowhere in my code do I dealloc!
Has anyone encountered this or a similar case? Any help is much appreciated!
UPDATE
I have filed a bug report with Apple after contacting developer support. Their engineers confirmed this as being a bug.