Open Radar

 
Crash report snippet:

Exception Type:        EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes:       0x0000000000000001, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Illegal instruction: 4
Termination Reason:    Namespace SIGNAL, Code 0x4
Terminating Process:   exc handler [0]

Application Specific Information:
crashed on child side of fork pre-exec
BUG IN CLIENT OF LIBPLATFORM: Unlock of an os_unfair_lock not owned by current thread

Thread 0 Crashed:
0   libsystem_platform.dylib      	0x00007fffdc761bf7 _os_unfair_lock_unowned_abort + 23
1   libsystem_platform.dylib      	0x00007fffdc761539 _os_unfair_lock_unlock_slow + 95
2   libBacktraceRecording.dylib   	0x00000001032d810c fork_child_process_handler + 23
3   libsystem_pthread.dylib       	0x00000001060fc54e _pthread_fork_child_postinit + 69
4   libSystem.B.dylib             	0x00007fffdafbfb50 libSystem_atfork_child + 64
5   libsystem_c.dylib             	0x00007fffdc598477 fork + 47

This happens when the libs from /usr/lib/system/introspection are used, e.g. when a process is launched from Xcode, on macOS Sierra Beta. It looks like fork_child_process_handler attempts to unlock a mutex in a child-side fork handler (pthread_atfork?), which fails and crashes the child.


Engineering has determined that your bug report is a duplicate of another issue and will be closed. 


The original report on your issue has been closed recently.  Please note that you will not be able to directly view the original report in order to keep its information confidential. 


This seemed to be fixed initially, but has started happening again on 10.12 Beta (16A313a):

Process:               <…> [32838]
Path:                  <…>
Identifier:            <…>
Version:               <…>
Code Type:             X86-64 (Native)
Parent Process:        <…> [32829]
Responsible:           <…> [32838]
User ID:               503

Date/Time:             2016-09-02 17:51:29.683 -0500
OS Version:            Mac OS X 10.12 (16A313a)
Report Version:        12
Anonymous UUID:        <…>


Time Awake Since Boot: 320000 seconds

System Integrity Protection: disabled

Crashed Thread:        0

Exception Type:        EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes:       0x0000000000000001, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Illegal instruction: 4
Termination Reason:    Namespace SIGNAL, Code 0x4
Terminating Process:   exc handler [0]

Application Specific Information:
crashed on child side of fork pre-exec
BUG IN CLIENT OF LIBPLATFORM: Unlock of an os_unfair_lock not owned by current thread

Thread 0 Crashed:
0   libsystem_platform.dylib      	0x00007fffa8e9cbf7 _os_unfair_lock_unowned_abort + 23
1   libsystem_platform.dylib      	0x00007fffa8e9c539 _os_unfair_lock_unlock_slow + 95
2   libBacktraceRecording.dylib   	0x00000001032f5d38 fork_child_process_handler + 23
3   libsystem_pthread.dylib       	0x000000010611654e _pthread_fork_child_postinit + 69
4   libSystem.B.dylib             	0x00007fffa76fab50 libSystem_atfork_child + 64
5   libsystem_c.dylib             	0x00007fffa8cd3477 fork + 47