CODEWITHSUNDEEP
iosobjective-c
Alberto Illobre
Alberto Illobre

Reputation: 45

iOS 10: Random Crashes in dispatch_async

I am developing an app under iOS 10, objective-c. The app runs fine from one to several hours until it crashes.

The strange thing is that the crash is always at the beginning of some block dispatch with dispatch_async (__gcd_queue_item_enqueue_hook_block_invoke). The block is never the same.

Tested leaks and varios malloc tests. Memory usage is low. It seems it is not a memory issue. Still nothing.

I am clueless at this point on how to proceed for debugging. Any suggestions welcome.

Edit: here is a complete stack trace from the last crash:

* thread #254, stop reason = EXC_BAD_ACCESS (code=1, address=0x24)
frame #0: 0x00000001006f2e08 libBacktraceRecording.dylib`__gcd_queue_item_enqueue_hook_block_invoke
frame #1: 0x00000001006f238c libBacktraceRecording.dylib`gcd_queue_item_enqueue_hook + 224
frame #2: 0x00000001012e5e48 libdispatch.dylib`_dispatch_introspection_queue_item_enqueue_hook + 40
frame #3: 0x00000001012c5304 libdispatch.dylib`_dispatch_queue_push + 196
* frame #4: 0x00000001000e2850 Lucky`-[LuckyViewController onEventsChanged:](self=0x000000010181a200, _cmd="onEventsChanged:", events=@"14 elements") at LuckyViewController.m:1517
frame #5: 0x00000001001f7c2c Lucky`-[TutorManager strategyLoop2](self=0x000000010165e4b0, _cmd="strategyLoop2") at TutorManager.m:723
frame #6: 0x000000018e62f318 Foundation`__NSThread__start__ + 996
frame #7: 0x000000018cbfd68c libsystem_pthread.dylib`_pthread_body + 240
frame #8: 0x000000018cbfd59c libsystem_pthread.dylib`_pthread_start + 284
frame #9: 0x000000018cbfacb4 libsystem_pthread.dylib`thread_start + 4

Upvotes: 0

Views: 437

Answers (1)

Lal Krishna
Lal Krishna

Reputation: 16190

This is not with dispatch_async.

Apple Technical Support confirmed that it's a bug within the libBacktraceRecording.dylib library, which is used for debugging within Xcode.

it won't crash on a users device since this is a debug error that occurs within a library not present on most users' devices.

In short, if you're seeing libBacktraceRecording.dylib at the top of your stack trace, it's probably this, and likely not an error in your code

Upvotes: 1

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