Hello everyone, I'm encountering an issue while trying to debug a macOS Action Extension. I created a completely fresh project with an Action Extension target. When I select the Action Extension scheme and run it, choosing Finder as the host app (app to launch it in), I receive the following error: Attach failed: Could not attach to pid : “647”. (Not allowed to attach to process. Look in the console messages (Console.app), near the debugserver entries, when the attach failed. The subsystem that denied the attach permission will likely have logged an informative message about why it was denied.) This is in Console.app: macOSTaskPolicy: (com.apple.debugserver) may not get the task control port of (Finder) (pid: 647): (Finder) is hardened, (Finder) doesn't have get-task-allow, (com.apple.debugserver) is a declared debugger(com.apple.debugserver) is not a declared read-only debugger. I am pretty sure it worked before on my project that I am developing. It stopped working and now it doesn't even work on a fresh new project. Any ideas? I tried cleaning derived data, restarting my mac, nothing helps. As per the documentation it should work normally using the Build & Run button.

I have a ZStack that contains a VStack with 2 views (view1 and view2) and a third view (view3). So, is either that view1 and View1 are visible, or view3 is visible. This is the relevant code: ZStack { VStack { view1() View2() } if showView3 View3() } view1 and view2 are 400px in width and 200px in height, while view3 is 400 x 400 px, so that it completely overwrite view1/view2 when visible. The problem I'm trying to solve is that the border of a TextField placed in view1 is visible when showView3 is true, what should not be happening (possible glitch in swift?). To show the problem, I prepared a code sample, which shows that when view3 is active, it completely overwrites view1/view2, but still, the border of the TextField remains visible. (See screenshot below) struct TestZStackView: View { @State private var showView3 = false var body: some View { ZStack { VStack { Toggle("view3", isOn: $showView3) View1() .frame(width: 400, height: 200) .background(Color.red) .zIndex(1) View2() .frame(width: 400, height: 200) .background(Color.green) .zIndex(1) } if showView3 { View3() .frame(width: 400, height: 400) .background(Color.blue) .zIndex(2) } } } } struct View1: View { var body: some View { TextField("Enter text", text: .constant("")) .padding() .cornerRadius(5) .textFieldStyle(RoundedBorderTextFieldStyle()) .zIndex(1) } } struct View2: View { var body: some View { Color.clear } } struct View3: View { var body: some View { Color.black // (Ensure no transparency) } } zIndex() are not required, I just placed them to see if the problem get solved, but it may no difference. BTW, in the code above, the visible border disappears if the view is minimized, but that is not the case in the real app I'm working on. In the screenshots attached, it can be seen how the TextField border remains visible when view3 is active ("https://developer.apple.com/forums/content/attachment/d0e75f25-d36e-4361-af64-54252d1f2a98" "title=Screenshot 2024-05-24 at 10.06.03 PM.png;width=800;height=632")

I have a ZStack that contains a VStack with 2 views (view1 and view2) and a third view (view3). So, is either that view1 and View1 are visible, or view3 is visible. This is the relevant code: ZStack { VStack { view1() View2() } if showView3 View3() } view1 and view2 are 400px in width and 200px in height, while view3 is 400 x 400 px, so that it completely overwrite view1/view2 when visible. The problem I'm trying to solve is that the border of a TextField placed in view1 is visible when showView3 is true, what should not be happening (possible glitch in swift?). To show the problem, I prepared a code sample, which shows that when view3 is active, it completely overwrites view1/view2, but still, the border of the TextField remains visible. (See screenshot below) struct TestZStackView: View { @State private var showView3 = false var body: some View { ZStack { VStack { Toggle("view3", isOn: $showView3) View1() .frame(width: 400, height: 200) .background(Color.red) .zIndex(1) View2() .frame(width: 400, height: 200) .background(Color.green) .zIndex(1) } if showView3 { View3() .frame(width: 400, height: 400) .background(Color.blue) .zIndex(2) } } } } struct View1: View { var body: some View { TextField("Enter text", text: .constant("")) .padding() .cornerRadius(5) .textFieldStyle(RoundedBorderTextFieldStyle()) .zIndex(1) } } struct View2: View { var body: some View { Color.clear } } struct View3: View { var body: some View { Color.black // (Ensure no transparency) } } zIndex() are not required, I just placed them to see if the problem get solved, but it may no difference. BTW, in the code above, the visible border disappears if the view is minimized, but that is not the case in the real app I'm working on. In the screenshots attached, it can be seen how the TextField border remains visible when view3 is active ("https://developer.apple.com/forums/content/attachment/d0e75f25-d36e-4361-af64-54252d1f2a98" "title=Screenshot 2024-05-24 at 10.06.03 PM.png;width=800;height=632")

Device type: iPad Air (5th generation) OS version: iOS 17.5 I don't know what to do.. I am using Firebase for auth and it work on every device. Except for the iPad Air. Does somebody have a similar issue? try { String email = _emailController.text; String password = _passwordController.text; if (EmailValidator.validate(email)) { await _auth.signInWithEmailAndPassword( email: email, password: password); } else { print("Ungültige E-Mail-Adresse"); } } catch (e) { print("Anmeldefehler: $e"); } } }

I have a view which is a form allowing me to edit details of a category item. In the toolbar, there is a button called "Cancel," whose sole function is to call the rollback function in the ModelContext class. This function should allow you to revert any changes made to the context. However, it appears that this rollback function is neither triggering the view update nor working properly, as I need to restart the app to see the changes reverted which just work when the property "isAutosaveEnabled" is set to false. Container configuration goes below import SwiftUI @main struct Index: App { var body: some Scene { WindowGroup { Window() } .modelContainer( for: [ Bill.self, Category.self ], isAutosaveEnabled: false, isUndoEnabled: true ) } } Rollback usage that don't work import SwiftUI import SwiftData import Foundation struct CategoryForm: View { @Environment(\.presentationMode) private var presentationMode @Environment(\.modelContext) private var modelContext @Bindable var category: Category var body: some View { NavigationStack { Form { Section( header: Text("Basic Information"), content: { TextField("Title", text: $category.name) } ) } .navigationTitle("New Category") .navigationBarTitleDisplayMode(.inline) .toolbar { // Cancel Button ToolbarItem( placement: .topBarLeading, content: { Button( action: onCancel, label: { Text("Cancel") } ) } ) // Done Button ToolbarItem( placement: .topBarTrailing, content: { Button( action: onDone, label: { Text("Done") } ) .disabled(category.name.isEmpty) } ) } } } func onCancel() { modelContext.rollback() presentationMode.wrappedValue.dismiss() } func onDone() { modelContext.insert(category) do { try modelContext.save() } catch { fatalError("Failed to save category") } presentationMode.wrappedValue.dismiss() } }

App crashing when clicking the icon of the app. Log:

I’m trying to track the location of the user on every 10-20 meters of the location change, I’ve managed to obtain the location updates while the application is in foreground or background using Backround modes. my issue is that I cannot get any updates after the application is terminated either by the user or by the system, I’ve tried using startMonitoringSignificantLocationChanges() but this does not fit my purpose since you get updates every 500m. Is it possible to achieve getting updates every 10 meters using “Region Monitoring”? Or is mobile device management (MDM) the only way to achieve this on an iOS device?

We started to see some crashes in our iOS app a few seconds after launch with the following reason: Exception Type: EXC_CRASH (SIGILL) Exception Codes: 0x0000000000000000, 0x0000000000000000 Termination Reason: SIGNAL 4 Illegal instruction: 4 when calling [NSPersistentContainer loadPersistentStoresWithCompletionHandler:]. I've looked through Understanding the exception types in a crash report page, but couldn't find this type there. Any ideas what could it be?

Recently we have started refactoring some code to use Swift concurrency in Xcode 15.3. As we have added some new async methods and Tasks, new runtime warnings have emerged titled "Known Hang" and several are listed. None of the stack traces listed with these warnings are in areas directly modified but some of the same types/methods called are also called from the modified areas. So I can sort of understand why they are coming up...but they had to have been there before we added the Swift concurrency. Example of a tooltip with the warnings: My first query is: Are these warnings only issued when Swift concurrency is added/applied (as they were not there when using closures and mostly just off the main thread to network calls)? The documentation indicates these can all be suppressed by turning off the Thread Performance Checker BUT I would rather just suppress the few places as we refactor our codebase (as it is quite large). In that way, any new ones may be documented and we can decide to fix them now or later. I have tried to follow the instructions and added an environment variable PERFC_SUPPRESSION_FILE (in the Scheme) with a full path to a file formatted similarly to the example in the documentation. class:NSManagedObjectContext method:-[NSManagedObjectContext save:] My second query is: I have verified that the variable is set by reading it from the ProcessInfo. However, regardless of my settings, the runtime warnings are still presented. I could not find any examples or even any mention of others using this environment variable. I am reaching out with any advice or ideas to try. Has anyone successfully tried this or found an issue/alternative? Help me Mr. Wizard!

We have an iOS app built using Capacitor. We are seeing a large increase in app crashes on iOS 17.4 (iPhone). Other OS versions seem to be showing significantly fewer crash numbers. We are unsure what is causing this, as our app did not go through any major releases. I have attached the crash log below. Thanks Exception Type: EXC_CRASH (SIGKILL) Exception Codes: 0x0000000000000000, 0x0000000000000000 Termination Reason: RUNNINGBOARD 0xd00d2bad

Xcode15 crash reloadItems - Invalid update: invalid number of items in section When building with xcode14, there was no crash when calling collectionView reloadItems. If you build with xcode15 A crash pops up saying Invalid update: invalid number of items in section. The current issue has been resolved, but I would like to know the exact cause of the crash in xcode 15. Does anyone know?

I've been encountering a strange crash that occurs randomly on my app's startup. The app compiles and (usually) runs just fine but every so often will close out immediately within a second or two of launching. I have found no methods to consistently reproduce this crash. Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Termination Reason: SIGNAL 6 Abort trap: 6 Last Exception Backtrace: 0 CoreFoundation 0x1a5498870 __exceptionPreprocess + 164 1 libobjc.A.dylib 0x19d7fbc00 objc_exception_throw + 60 2 CoreFoundation 0x1a551d4f8 -[NSException init] + 0 3 Foundation 0x1a439877c -[NSObject(NSKeyValueCoding) setValue:forKey:] + 284 4 UIKitCore 0x1a796b188 -[UIViewController setValue:forKey:] + 80 5 UIKitCore 0x1a796b10c -[UIRuntimeOutletConnection connect] + 84 I would include the full crash report but for the URL needed for file attachments contains sensitive language somehow?? Any help resolving this issue would be greatly appreciated.

I've been encountering a strange crash that occurs randomly on my app's startup. The app compiles and (usually) runs just fine. I have found no methods to consistently reproduce this crash. I would provide the exception backtrace, but for some reason it's being flagged as sensitive language?? So instead I've attached the full crash log for anyone who is interested. Any help resolving this issue would be greatly appreciated.

I have the Vision Pro developer strap, do I need to do anything to make Instruments transfer the data over it rather than wifi? Or will it do that automatically? It seems incredibly slow for transferring and then analysing data. I can see the Vision Pro recognised in Configurator, so assume it's working. Otherwise.. Any tips for speeding up Instruments? Capturing 5 mins of gameplay (high-freq) then takes 30-40+ mins to appear in Instruments on an M2 Max 32gb. Thanks!

I have a complex project that includes a background process sending requests to the backend for updates. It sends requests once per second. So, I have the MyView where the PresetPicker is located. When I open the PresetPicker and try to scroll down, it keeps pushing me back up every second. PresetPicker redraws itself every second due to some changes from the background process. (Turning off the background process confirmed that everything works fine.) I wrapped my PresetPicker in EquatableView, added a bunch of logs triggered by changes/redraws of the PresetPicker, but the logs are empty and EquatableView didn't help. I tried setting breakpoints; they trigger when the PresetPicker first appears but don't trigger afterward. How can I fix/debug this? Here is some code: struct PresetPicker: View, Equatable { var body: some View { Menu { Text("1") Text("2") Text("3") Text("4") } label: { Text("menu") } } } struct MyView: View { var body: some View { EquatableView(content: PresetPicker() ) } }

I have recently submitted a new app version to the Appstore with Xcode 15.0. Unfortunately, I have started to see the below crash in the Xcode organiser > Crashes section occurring for more number of times. UIKitCore: +[UIAlertController _alertControllerContainedInViewController:] + 160 The exception trace is not leading to main() function but not pointing to any of the code line. I had used UIAlertController in the past versions to show the alerts but there is no code written in the current version code related to UIAlertController. Only from the latest version, this kind of crash started to surface. In the latest release, We have added a third party SDK and while implementing the SDK, we had added the Location and Bluetooth Permissions in Info.plist file. But as we don't want to use/track the Location and Bluetooth details from the app, the SDK team has disabled the Location and Bluetooth settings to not reflect in the tracked data. Is this behaviour creating any conflict with the UIAlertController and logging the crash? Because by default the OS tries to show the alert when the permissions exist in the plist file, but the alert will not come as the service is disabled on the SDK server settings. Is this creating any conflict and logging the crash. Please extend your help.

Before iOS 17, CTFrameGetLines(ctFrame) returns exact number of lines it will displayed on the screen. However after iOS 17.2.x, under some unknown condition, it returns less CTLines. It's easy to reproduce: let formattedString = NSMutableAttributedString() formattedString.append(.init(string: "你", attributes: [.font: UIFont.boldSystemFont(ofSize: 14)])) formattedString.append(.init(string: "\n\n\n\n\n\n好\n")) let ctSetter = CTFramesetterCreateWithAttributedString(formattedString as CFAttributedString) let rect = CGRect(x: 0, y: 0, width: 100, height: 1000) let bezierPath = UIBezierPath(rect: rect) let ctFrame = CTFramesetterCreateFrame(ctSetter, CFRangeMake(0, formattedString.length), bezierPath.cgPath, nil) let ctLines = CTFrameGetLines(ctFrame) print("CTLine count: \(CFArrayGetCount(ctLines))") The test code above should print CTLine count: 7, but actually it returns 4. One weird CTLine is like: - 1 : <CTLine: 0x3031e0780>{run count = 1, string range = (2, 3), width = 0, A/D/L = 9.24023/2.75977/0, glyph count = 3, runs = ( <CTRun: 0x10173ec50>{string range = (2, 3), string = "\n\n\n", attributes = { NSFont = "<UICTFont: 0x101728800> font-family: \"Helvetica\"; font-weight: normal; font-style: normal; font-size: 12.00pt"; }} ) } never met this issue before, is it a bug or just new feature...

Hi, Looking for some guidance on getting my code approved through app connect. Based on the crash logs, it appears the application is experiencing crashes related to an EXC_CRASH (SIGABRT), which is typically triggered by the app receiving an abort signal, often as a result of an unhandled exception or other critical errors that cause the app to terminate abruptly. Any ideas on how to resolve?

Over the years I’ve helped a lot of folks investigate a lot of crashes. In some cases those crashes only make sense if you know a little about how Foundation and Core Foundation types are toll-free bridged. This post is my attempt to explain that. If you have questions or comments, please put them in a new thread. Tag it with Foundation and Debugging so that I see it. Share and Enjoy — Quinn “The Eskimo!” @ Devel oper Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Crashes on the Toll-Free Bridge Certain Core Foundation (CF) types are toll-free bridged to their Foundation equivalent. That allows you to pass the Foundation object to a CF routine and vice versa [1]. For example, NSData and CFData are toll-free bridged, allowing you to pass an NSData object to a CF routine like CFDataGetBytePtr. For more information on this topic, see Toll-Free Bridged Types within Core Foundation Design Concepts in the Documentation Archive. This is cool, but it does present some interesting challenges. One of these relates to subclassing. Many of the toll-free bridge Foundation types support subclassing and, if you create a instance of your subclass and pass it to CF, CF has to do the right thing. Continuing the NSData example above, it’s legal [2] to create your own subclass of NSData with a completely custom implementation. As long as you implement the -bytes method and the length property, all the other NSData methods will just work. Moreover, this class works with CFData routines as well. If you pass an instance of your subclass to CFDataGetBytePtr, CF detects that it’s an Objective-C object and calls your -bytes method. Exciting! So, how does this actually work? It relies on the fact that CF and Objective-C types share a common object header. That object header is an implementation detail, but the first word of the header is always an indication of the class [3]. CF uses this word to distinguish between CF and Objective-C objects. Note This basic technique is used by other Objective-C compatible types, including Swift objects and XPC objects. If, for example, you call CFRetain on Swift object, it detects that this is an Objective-C compatible object and calls objc_retain, which in turns detects that this is a Swift object and calls swift_retain. To see this in action, check out the Swift Foundation open source. Continuing our NSData example, the first line of CFDataGetBytePtr uses the CF_OBJC_FUNCDISPATCHV macro to check if this is an Objective-C object and, if so, call -bytes on it. Sadly, the open source trail goes cold here, because Objective-C integration is only supported on Apple platforms. However, some disassembly reveals the presence of an internal routine called CF_IS_OBJC. (lldb) disas -n CFDataGetBytePtr CoreFoundation`CFDataGetBytePtr: … <+0>: pacibsp … <+4>: stp x20, x19, [sp, #-0x20]! … <+8>: stp x29, x30, [sp, #0x10] … <+12>: add x29, sp, #0x10 … <+16>: mov x19, x0 … <+20>: mov w0, #0x14 … <+24>: mov x1, x19 … <+28>: bl 0x19cc60100 ; CF_IS_OBJC … WARNING Do not rely on the presence or behaviour of CF_IS_OBJC. This is an implementation detail. It has changed many times in the past and may well change in the future [4]. While this is an implementation detail, it’s useful to know about when debugging. If you pass something that’s not a valid object to CFDataGetBytePtr, you might see it crash in CF_IS_OBJC. For example, this code: void test(void) { struct { int i; } s = { 0 }; CFDataGetBytePtr( (const struct __CFData *) &s ); } crashes like this: Exception Type: EXC_BREAKPOINT (SIGTRAP) … Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 CoreFoundation … CF_IS_OBJC + 76 1 CoreFoundation … CFDataGetBytePtr + 32 2 xxot … test + 24 … … In this case CF_IS_OBJC has detected the problem and trapped, resulting in an EXC_BREAKPOINT crash. However, if you pass it a pointer that looks more like an object, this might crash trying to dereference a bad pointer, which will result in a EXC_BAD_ACCESS crash. The other common failure you see occurs when you pass it an Objective-C object of the wrong type. Consider code like this: void test(void) { id str = [NSString stringWithFormat:@"Hello Cruel World!-%d", (int) getpid()]; const void * ptr = CFDataGetBytePtr( (__bridge CFDataRef) str); … } When you run this code, it throws a language exception like this: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString bytes]: unrecognized selector sent to instance 0x6000028545a0' *** First throw call stack: ( 0 CoreFoundation … __exceptionPreprocess + 176 1 libobjc.A.dylib … objc_exception_throw + 60 2 CoreFoundation … -[NSObject(NSObject) __retain_OA] + 0 3 CoreFoundation … ___forwarding___ + 1580 4 CoreFoundation … _CF_forwarding_prep_0 + 96 5 xxot … test + 92 … ) CFDataGetBytePtr has detected this is an Objective-C object and called -bytes on it. However, this is actually an NSString [5] and NSString doesn’t implement the -bytes method. The end result is an unrecognized selector exception. [1] To be clear, when using CF objects in Objective-C you first cast the CF object to its Foundation equivalent and then call Objective-C methods on it. [2] While it’s legal to do this, it’s probably not very sensible. Subclassing Foundation types is something that might’ve made sense back in the day, but these days there are generally better ways to solve your problems. [3] Historically this word was called isa and was of type Class, that is, a pointer to the actual Objective-C class. These days things are much more complex (-: [4] Historically, CF_IS_OBJC was very simple: If the object’s isa word was 0, it was a CF object, otherwise it was an Objective-C object. That’s no longer the case. [5] The actual type is __NSCFString. That’s because NSString is a class cluster. For more about that, see Class Clusters within Cocoa Fundamentals Guide in the Documentation Archive.

Our app collected some JavaScriptCore crash information on iOS17 and above systems, but the cause of the error cannot be located. The crash stack is as follows: #27 Heap Helper Thread SIGSEGV 0 JavaScriptCore JSC::MarkedBlock::aboutToMarkSlow(unsigned int) 1 JavaScriptCore JSC::JSFinalObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&amp;amp;) 2 JavaScriptCore JSC::JSFinalObject::visitChildren(JSC::JSCell*, JSC::SlotVisitor&amp;amp;) 3 JavaScriptCore JSC::SlotVisitor::drain(***::MonotonicTime) 4 JavaScriptCore JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, ***::MonotonicTime) 5 JavaScriptCore ***::SharedTaskFunctor&amp;lt;void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_15&amp;gt;::run() 6 JavaScriptCore ***::ParallelHelperClient::runTask(***::RefPtr&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt;, ***::RawPtrTraits&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt; &amp;gt;, ***::DefaultRefDerefTraits&amp;lt;***::SharedTask &amp;lt;void ()&amp;gt; &amp;gt; &amp;gt; const&amp;amp;) 7 JavaScriptCore ***::ParallelHelperPool::Thread::work() 8 JavaScriptCore ***::Detail::CallableWrapper&amp;lt;***::AutomaticThread::start(***::AbstractLocker const&amp;amp;)::$_0, void&amp;gt;::call() 9 JavaScriptCore ***::Thread::entryPoint(***::Thread::NewThreadContext*) 10 JavaScriptCore ***::wtfThreadEntryPoint(void*) 11 libsystem_pthread.dylib __pthread_start #1 Queue: com.apple.main-thread SIGSEGV 0 libobjc.A.dylib _objc_msgSend 1 UIKitCore -[UIView(Geometry) convertPoint:toView:] #24 JSC Heap Collector Thread SIGSEGV 0 libsystem_kernel.dylib ___psynch_cvwait 1 libsystem_pthread.dylib __pthread_cond_wait 2 JavaScriptCore ***::ThreadCondition::timedWait(***::Mutex&amp;amp;, ***::WallTime) 3 JavaScriptCore ***::ParkingLot::parkConditionallyImpl(void const*, ***::ScopedLambda&amp;lt;bool ()&amp;gt; const&amp;amp;, ***::ScopedLambda&amp;lt;void ()&amp;gt; const&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 4 JavaScriptCore bool ***::Condition::waitUntilUncheckedWTF::Lock(***::Lock&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 5 JavaScriptCore JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, ***::MonotonicTime) 6 JavaScriptCore JSC::Heap::runConcurrentPhase(JSC::GCConductor) 7 JavaScriptCore JSC::Heap::runCurrentPhase(JSC::GCConductor, JSC::CurrentThreadState*) 8 JavaScriptCore JSC::Heap::HeapThread::work() 9 JavaScriptCore ***::Detail::CallableWrapper&amp;lt;***::AutomaticThread::start(***::AbstractLocker const&amp;amp;)::$_0, void&amp;gt;::call() 10 JavaScriptCore ***::Thread::entryPoint(***::Thread::NewThreadContext*) 11 JavaScriptCore ***::wtfThreadEntryPoint(void*) 12 libsystem_pthread.dylib __pthread_start #25 Heap Helper Thread SIGSEGV 0 libsystem_kernel.dylib ___psynch_cvwait 1 libsystem_pthread.dylib __pthread_cond_wait 2 JavaScriptCore ***::ThreadCondition::timedWait(***::Mutex&amp;amp;, ***::WallTime) 3 JavaScriptCore ***::ParkingLot::parkConditionallyImpl(void const*, ***::ScopedLambda&amp;lt;bool ()&amp;gt; const&amp;amp;, ***::ScopedLambda&amp;lt;void ()&amp;gt; const&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 4 JavaScriptCore bool ***::Condition::waitUntilUncheckedWTF::Lock(***::Lock&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 5 JavaScriptCore JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, ***::MonotonicTime) 6 JavaScriptCore ***::SharedTaskFunctor&amp;lt;void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_15&amp;gt;::run() 7 JavaScriptCore ***::ParallelHelperClient::runTask(***::RefPtr&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt;, ***::RawPtrTraits&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt; &amp;gt;, ***::DefaultRefDerefTraits&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt; &amp;gt; &amp;gt; const&amp;amp;) 8 JavaScriptCore ***::ParallelHelperPool::Thread::work() 9 JavaScriptCore ***::Detail::CallableWrapper&amp;lt;***::AutomaticThread::start(***::AbstractLocker const&amp;amp;)::$_0, void&amp;gt;::call() 10 JavaScriptCore ***::Thread::entryPoint(***::Thread::NewThreadContext*) 11 JavaScriptCore ***::wtfThreadEntryPoint(void*) 12 libsystem_pthread.dylib __pthread_start #27 Heap Helper Thread SIGSEGV 0 libsystem_kernel.dylib ___psynch_cvwait 1 libsystem_pthread.dylib __pthread_cond_wait 2 JavaScriptCore ***::ThreadCondition::timedWait(***::Mutex&amp;amp;, ***::WallTime) 3 JavaScriptCore ***::ParkingLot::parkConditionallyImpl(void const*, ***::ScopedLambda&amp;lt;bool ()&amp;gt; const&amp;amp;, ***::ScopedLambda&amp;lt;void ()&amp;gt; const&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 4 JavaScriptCore bool ***::Condition::waitUntilUncheckedWTF::Lock(***::Lock&amp;amp;, ***::TimeWithDynamicClockType const&amp;amp;) 5 JavaScriptCore JSC::SlotVisitor::drainFromShared(JSC::SlotVisitor::SharedDrainMode, ***::MonotonicTime) 6 JavaScriptCore ***::SharedTaskFunctor&amp;lt;void (), JSC::Heap::runBeginPhase(JSC::GCConductor)::$_15&amp;gt;::run() 7 JavaScriptCore ***::ParallelHelperClient::runTask(***::RefPtr&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt;, ***::RawPtrTraits&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt; &amp;gt;, ***::DefaultRefDerefTraits&amp;lt;***::SharedTask&amp;lt;void ()&amp;gt; &amp;gt; &amp;gt; const&amp;amp;) 8 JavaScriptCore ***::ParallelHelperPool::Thread::work() 9 JavaScriptCore ***::Detail::CallableWrapper&amp;lt;***::AutomaticThread::start(***::AbstractLocker const&amp;amp;)::$_0, void&amp;gt;::call() 10 JavaScriptCore ***::Thread::entryPoint(***::Thread::NewThreadContext*) 11 JavaScriptCore ***::wtfThreadEntryPoint(void*) 12 libsystem_pthread.dylib __pthread_start Please help analyze and locate the cause. Has anyone else encountered this problem?