Crashes in ImageCaptureCore framework

Please post a full Apple crash report for this, using the advice from Posting a Crash Report.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hey Quinn and thanks million!

Wauw, I didn't even know that you could see the crash-log-files in Xcode by right-clicking and choose 'Show in Finder' 😅

(As explained we are unable to reproduce this by ourselves. So we only have crash-reports from end-users.)

Here's five from the 'remoteCameraWithFailureBlock' type...

Cheers!

1. 2023-09-15_11-30-06.8328_-0700-2d7d19b4b44c0ea3103ecdf7cfd26b1e7ef1a6f8.crash
2. 2023-09-15_17-26-21.4373_+0800-19859941dca81973829d2a5442f13bc22b0dfa4c.crash
3. 2023-09-17_12-28-10.4574_+0900-780b6a777e9ebef887a60c4a98828348208a93e7.crash
4. 2023-09-20_13-33-32.3042_+1000-1be91b2f3a0a083a3f85e788ea63beb396f1475c.crash
5. 2023-09-13_19-02-17.9793_-0500-b0abc39ce89f7436a9be550d4046b278ca499416.crash

Thanks for the crash reports.

I ran these through an internal system and AFAIK these crashes are very specific to your app. That suggests one of two things:

• There’s a bug in your code that’s causing this.

• There’s a very obscure bug in the system that only your app manages to trigger.

In situation like this I normally favour the first option, but the API you’re using is fairly obscure.

The other thing about the crash reports is that they all suggest a memory management issue. A typical backtrace looks like this:

Thread 51 name:
Thread 51 Crashed:
0  libobjc.A.dylib         … objc_msgSend + 8 (:-1)
1  ImageCaptureCore        … __47-[ICCameraDevice remoteCameraWithFailureBlock:]_block_invoke + 188 (ICCameraDe…
2  Foundation              … __NSXPCCONNECTION_IS_CALLING_OUT_TO_ERROR_BLOCK__ + 24 (NSXPCConnection.m:217)
3  Foundation              … __88-[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:w…
4  libxpc.dylib            … _xpc_connection_reply_callout + 124 (serializer.c:119)
5  libxpc.dylib            … _xpc_connection_call_reply_async + 88 (connection.c:891)
6  libdispatch.dylib       … _dispatch_client_callout3 + 20 (object.m:586)
7  libdispatch.dylib       … _dispatch_mach_msg_async_reply_invoke + 344 (mach.c:3102)
8  libdispatch.dylib       … _dispatch_lane_serial_drain + 372 (queue.c:3885)
9  libdispatch.dylib       … _dispatch_lane_invoke + 436 (queue.c:3976)
10 libdispatch.dylib       … _dispatch_workloop_worker_thread + 648 (queue.c:6507)
11 libsystem_pthread.dylib … _pthread_wqthread + 288 (pthread.c:2618)
12 libsystem_pthread.dylib … start_wqthread + 8 (:-1)

Frames 12 through 6 are standard Dispatch run-a-block-on-a-queue code. Frames 5 and 4 are core XPC code, processing a reply callback. Frames 3 and 2 are the NSXPCConnection code layered on top of that. Frame 1 is a reply block within -[ICCameraDevice remoteCameraWithFailureBlock:]. Frame 0 is the Objective-C runtime crashing. The runtime is essentially bug free, which means that the only way it can crash is if it was passed a bogus object.

That doesn’t tell us where the bogus object came from, alas. In situations like this I usually prescribe a course of the standard memory debugging tools. If you’re lucky these will make the problem more reproducible, which will allow you to debug it further.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hi @eskimo ,

I have the crash issue too in ImageCaptureCore framework. In our app, we executed a looping async-await process by using requestSendPTPCommand(_:outData:completion:).

The crash occurred if the application keep executed the looping async-await process in some minutes (in my case is about 15 minutes). The crash log has been obtained from the crashed device, but I have problem when I uploaded it as attachment, it keeps raise me error with message "An error occured while uploading this log. Please try again later."

So that, herewith I attach some images instead:

There is "remoteCameraWithFailureBlock" mentioned in Thread 4 block, same with @bims case.

Any help to find the cause would be very helpful and appreciated. Why the crash only happen for a while? Not explicitly reproduced in an exact event.

I have problem when I uploaded it as attachment

Bummer. I’ve just updated Posting a Crash Report with some advice as to what to do in this case.

Also, honestly, I suspect that this was a transient error and, if you retry now, it’ll just work.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hi @eskimo :)

Problem solved!

At some point I changed from using a delegate-based version of requestSendPTPCommand (ImageCaptureCore) to use block-based version. The reason for this change was to support iOS 15.0 in addition to macOS. And the delegate-based version wasn't support in iOS back then (first introduced in iOS 15.2).

But now I realized that the method was called from an C++ object and not Objective C object! (In a .m-file mixed with both C++ and Objective C classes 🥹.)

Changing it to delegate-based version where the delegate was an Objective C object made it work again smoothly :)

Thanks again for your help and time on this!

你好，请问可以参考一下iOS应用使用 ImageCaptureCore 框架与相机进行 PTP 通信的代码吗，我现在可以获取设备的基本信息，但是使用PTP接口与相机通信出现IO错误，测试了其他应用没有问题。 感谢。