How to find the cause of an exception

I am trying to debug a crash whenever an iOS document provider extension is started. As it is a extension I am not able to debug it correctly, and this error log is the best i was able to get out of the device. How can i see what is throwing the exception (or what the assertion is) when none of the methods that get called are mine.

Incident Identifier: 0B4EA724-9AFB-4EE3-B752-7E1FDF3B9A75
CrashReporter Key:   ac4cdaa3c5ddd65a3bffef5cc28903f683f0309d
Hardware Model:      iPad3,1
Process:             FileProvider [1100]
Path:                /private/var/containers/Bundle/Application/CEDD148D-420D-4BE8-ABF8-8E83F6385ABC/Privat.app/PlugIns/FileProvider.appex/FileProvider
Identifier:          com.privat.cloud.FileProvider
Version:             1 (2.5.6)
Code Type:           ARM (Native)
Parent Process:      launchd [1]

Date/Time:           2017-02-09 15:19:03.03 +0100
Launch Time:         2017-02-09 15:19:02.02 +0100
OS Version:          iOS 9.3.5 (13G36)
Report Version:      105

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Triggered by Thread:  0

Filtered syslog:
None found

Last Exception Backtrace:
0   CoreFoundation                  0x22673916 __exceptionPreprocess + 122
1   libobjc.A.dylib                 0x21e0ee12 objc_exception_throw + 34
2   CoreFoundation                  0x226737ec +[NSException raise:format:arguments:] + 100
3   Foundation                      0x22e57524 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 88
4   UIKit                           0x26fc83e0 -[UIDocumentPickerExtensionViewController _prepareWithExtensionInfo:completionHandler:] + 504
5   CoreFoundation                  0x226784c0 __invoking___ + 64
6   CoreFoundation                  0x2259e878 -[NSInvocation invoke] + 288
7   CoreFoundation                  0x225a22f2 -[NSInvocation invokeWithTarget:] + 46
8   UIKit                           0x27489390 -[_UIViewServiceImplicitAnimationDecodingProxy forwardInvocation:] + 252
9   CoreFoundation                  0x22676d7e ___forwarding___ + 346
10  CoreFoundation                  0x225a2234 _CF_forwarding_prep_0 + 20
11  CoreFoundation                  0x226784c0 __invoking___ + 64
12  CoreFoundation                  0x2259e878 -[NSInvocation invoke] + 288
13  CoreFoundation                  0x225a22f2 -[NSInvocation invokeWithTarget:] + 46
14  UIKit                           0x27408b32 -[_UIQueueingProxy forwardInvocation:] + 370
15  CoreFoundation                  0x22676d7e ___forwarding___ + 346
16  CoreFoundation                  0x225a2234 _CF_forwarding_prep_0 + 20
17  CoreFoundation                  0x226784c0 __invoking___ + 64
18  CoreFoundation                  0x2259e878 -[NSInvocation invoke] + 288
19  CoreFoundation                  0x225a22f2 -[NSInvocation invokeWithTarget:] + 46
20  CoreFoundation                  0x22676d7e ___forwarding___ + 346
21  CoreFoundation                  0x225a2234 _CF_forwarding_prep_0 + 20
22  CoreFoundation                  0x226784c0 __invoking___ + 64
23  CoreFoundation                  0x2259e878 -[NSInvocation invoke] + 288
24  CoreFoundation                  0x225a22f2 -[NSInvocation invokeWithTarget:] + 46
25  CoreFoundation                  0x22676d7e ___forwarding___ + 346
26  CoreFoundation                  0x225a2234 _CF_forwarding_prep_0 + 20
27  CoreFoundation                  0x226784c0 __invoking___ + 64
28  CoreFoundation                  0x2259e878 -[NSInvocation invoke] + 288
29  FrontBoardServices              0x23d16c02 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 14
30  FrontBoardServices              0x23d16ab4 -[FBSSerialQueue _performNext] + 220
31  FrontBoardServices              0x23d16db4 -[FBSSerialQueue _performNextFromRunLoopSource] + 44
32  CoreFoundation                  0x22635dfa __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 10
33  CoreFoundation                  0x226359e8 __CFRunLoopDoSources0 + 448
34  CoreFoundation                  0x22633d56 __CFRunLoopRun + 790
35  CoreFoundation                  0x22583224 CFRunLoopRunSpecific + 516
36  CoreFoundation                  0x22583010 CFRunLoopRunInMode + 104
37  GraphicsServices                0x23b73ac4 GSEventRunModal + 156
38  UIKit                           0x26c57184 UIApplicationMain + 140
39  libxpc.dylib                    0x223cd07c _xpc_objc_main + 700
40  libxpc.dylib                    0x223ce730 xpc_main + 164
41  Foundation                      0x22f74790 -[NSXPCListener resume] + 160
42  PlugInKit                       0x28afe128 -[PKService run] + 504
43  PlugInKit                       0x28afddf6 +[PKService main] + 54
44  PlugInKit                       0x28afe15c +[PKService _defaultRun:arguments:] + 16
45  libextension.dylib              0x22db37c8 NSExtensionMain + 44
46  libdyld.dylib                   0x2222b86e tlv_get_addr + 42


Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libsystem_kernel.dylib          0x222fec5c __pthread_kill + 8
1   libsystem_pthread.dylib         0x223a8732 pthread_kill + 62
2   libsystem_c.dylib               0x222930ac abort + 108
3   libc++abi.dylib                 0x21deaae4 __cxa_bad_cast + 0
4   libc++abi.dylib                 0x21e0369e default_terminate_handler() + 266
5   libobjc.A.dylib                 0x21e0f0b0 _objc_terminate() + 192
6   libc++abi.dylib                 0x21e00e16 std::__terminate(void (*)()) + 78
7   libc++abi.dylib                 0x21e008f8 __cxa_increment_exception_refcount + 0
8   libobjc.A.dylib                 0x21e0ef5e objc_exception_rethrow + 42
9   CoreFoundation                  0x225832ae CFRunLoopRunSpecific + 654
10  CoreFoundation                  0x22583014 CFRunLoopRunInMode + 108
11  GraphicsServices                0x23b73ac8 GSEventRunModal + 160
12  UIKit                           0x26c57188 UIApplicationMain + 144
13  libxpc.dylib                    0x223cd080 _xpc_objc_main + 704
14  libxpc.dylib                    0x223ce734 xpc_main + 168
15  Foundation                      0x22f74794 service_connection_handler + 0
16  PlugInKit                       0x28afe12c -[PKService run] + 508
17  PlugInKit                       0x28afddfa +[PKService main] + 58
18  PlugInKit                       0x28afe160 +[PKService _defaultRun:arguments:] + 20
19  libextension.dylib              0x22db37cc NSExtensionMain + 48
20  libdyld.dylib                   0x2222b872 start + 2

Thread 1:
0   libsystem_kernel.dylib          0x222ff864 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x223a5b34 _pthread_wqthread + 1036
2   libsystem_pthread.dylib         0x223a5718 start_wqthread + 8

Thread 2 name:  Dispatch queue: com.apple.libdispatch-manager
Thread 2:
0   libsystem_kernel.dylib          0x223002f8 kevent_qos + 24
1   libdispatch.dylib               0x221f5d60 _dispatch_mgr_invoke + 256
2   libdispatch.dylib               0x221f5abe _dispatch_mgr_thread$VARIANT$mp + 38

Thread 3:
0   libsystem_kernel.dylib          0x222ff864 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x223a5b34 _pthread_wqthread + 1036
2   libsystem_pthread.dylib         0x223a5718 start_wqthread + 8

Thread 4:
0   libsystem_kernel.dylib          0x222ff864 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x223a5b34 _pthread_wqthread + 1036
2   libsystem_pthread.dylib         0x223a5718 start_wqthread + 8

Thread 5:
0   libsystem_kernel.dylib          0x222ff864 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x223a5b34 _pthread_wqthread + 1036
2   libsystem_pthread.dylib         0x223a5718 start_wqthread + 8

Thread 6 name:  com.apple.coremedia.player.async
Thread 6:
0   libsystem_kernel.dylib          0x222ea920 semaphore_wait_trap + 8
1   libdispatch.dylib               0x221f294a _dispatch_semaphore_wait_slow + 190
2   MediaToolbox                    0x279571ec fpa_AsyncMovieControlThread + 1916
3   CoreMedia                       0x2462b9b8 figThreadMain + 208
4   libsystem_pthread.dylib         0x223a785a _pthread_body + 138
5   libsystem_pthread.dylib         0x223a77ce _pthread_start + 110
6   libsystem_pthread.dylib         0x223a5724 thread_start + 8

Thread 0 crashed with ARM Thread State (32-bit):
    r0: 0x00000000    r1: 0x00000000      r2: 0x00000000      r3: 0x00000000
    r4: 0x00000006    r5: 0x395c3000      r6: 0x38803304      r7: 0x0037e378
    r8: 0x14582d00    r9: 0x21e048fd     r10: 0x3428ff05     r11: 0x14582d24
    ip: 0x00000148    sp: 0x0037e36c      lr: 0x223a8733      pc: 0x222fec5c
  cpsr: 0x00000010

If i setup a global exception breakpoint i get this, and it is not helpful:

libobjc.A.dylib`objc_exception_throw:
->  0x23c5edf0 <+0>:   push   {r4, r5, r6, r7, lr}
    0x23c5edf2 <+2>:   add    r7, sp, #0xc
    0x23c5edf4 <+4>:   .long  0x0d00e92d                ; unknown opcode
    0x23c5edf8 <+8>:   .long  0x6dfaf5ad                ; unknown opcode
    0x23c5edfc <+12>:  mov    r5, r0
    0x23c5edfe <+14>:  movs   r0, #0x10
    0x23c5ee00 <+16>:  bl     0x23c5027c                ; __cxa_allocate_exception