Crash with GCD

Question

mrdekk2 OP

Created Aug ’17

Replies 1

Boosts 0

Views 1.8k

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Good day!

I'm getting some crashes with call to func _dispatch_set_priority_and_voucher_slow

It occurs in different situations and in different libraries, but stack trace for this thread is always the same, like this

Thread 6 name:  Dispatch queue: com.apple.root.default-qos.overcommit
Thread 6 Crashed:
0   libdispatch.dylib               0x0000000186b95b78 _dispatch_set_priority_and_voucher_slow + 164
1   libdispatch.dylib               0x0000000186b9912c _dispatch_queue_override_invoke + 732
2   libdispatch.dylib               0x0000000186b9912c _dispatch_queue_override_invoke + 732
3   libdispatch.dylib               0x0000000186b9aa50 _dispatch_root_queue_drain + 540
4   libdispatch.dylib               0x0000000186b9a7d0 _dispatch_worker_thread3 + 124
5   libsystem_pthread.dylib         0x0000000186d93100 _pthread_wqthread + 1096

I have no idea why. In which direction should I investigate further.

Meta of such crashes (some fields ommited intentionally):

Incident Identifier: 68347030-75A2-4B65-87AF-E2727AD0B8CE
CrashReporter Key:   b87b0b8d6c6ac6f12534cf2182c7f70b62b08ca3
Hardware Model:      iPhone7,2
Code Type:       ARM-64
Parent Process:  ? [1]


Date/Time:       2017-08-16 09:31:05.000 +0300
OS Version:      iOS 10.3.3 (14G60)
Report Version:  104


Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: 0x00000000 at 0x000000000008e8d8
Crashed Thread:  6

Thank you

Boost

Answer 1

QuinceyMorris OP

Aug ’17

My guess is you have a memory management problem where something (perhaps a block passed to GCD rather than a data object) is being overreleased. As with your other bug, you can try submitting a bug report.

The fact that the stack trace is always the same is good news. That (vaguely) suggests the problem has a single point of error, and could perhaps be made repeatable at will. That makes it much easier to debug.

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