➜  dev.mongo git:(master) ✗ lldb -- ./mongod 
(lldb) target create "./mongod"
Current executable set to './mongod' (x86_64).
(lldb) r
Process 24578 launched: './mongod' (x86_64)
Process 24578 stopped
* thread #1: tid = 0x1f7f86, 0x00007fff95ecc135 libsystem_platform.dylib`_platform_memmove$VARIANT$Haswell + 533, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x1036ffffd)
    frame #0: 0x00007fff95ecc135 libsystem_platform.dylib`_platform_memmove$VARIANT$Haswell + 533
libsystem_platform.dylib`_platform_memmove$VARIANT$Haswell:
->  0x7fff95ecc135 <+533>: vmovups -0x40(%rsi), %ymm2
    0x7fff95ecc13a <+538>: subq   $0x40, %rsi
    0x7fff95ecc13e <+542>: subq   $0x40, %rdx
    0x7fff95ecc142 <+546>: ja     0x7fff95ecc122            ; <+514>
(lldb) bt
* thread #1: tid = 0x1f7f86, 0x00007fff95ecc135 libsystem_platform.dylib`_platform_memmove$VARIANT$Haswell + 533, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x1036ffffd)
  * frame #0: 0x00007fff95ecc135 libsystem_platform.dylib`_platform_memmove$VARIANT$Haswell + 533
    frame #1: 0x00007fff9d07b225 libc++.1.dylib`std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init(char const*, unsigned long) + 91
    frame #2: 0x00000001000231eb mongod`mongo::BSONElement::str() const [inlined] std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(this=<unavailable>, __s=<unavailable>, __n=<unavailable>) + 155 at string:2024
    frame #3: 0x00000001000231e0 mongod`mongo::BSONElement::str() const [inlined] std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(__s=<unavailable>, __n=<unavailable>) at string:2022
    frame #4: 0x00000001000231e0 mongod`mongo::BSONElement::str(this=<unavailable>) const + 144 at bsonelement.h:359
    frame #5: 0x000000010063e136 mongod`mongo::StorageEngineMetadata::read() [inlined] mongo::BSONElement::String(this=<unavailable>) const + 3734 at bsonelement.h:79
    frame #6: 0x000000010063e116 mongod`mongo::StorageEngineMetadata::read(this=0x0000000103300c40) + 3702 at storage_engine_metadata.cpp:182
    frame #7: 0x000000010063d0a3 mongod`mongo::StorageEngineMetadata::forPath(dbpath=<unavailable>) + 259 at storage_engine_metadata.cpp:70
    frame #8: 0x000000010063ec72 mongod`mongo::StorageEngineMetadata::getStorageEngineForPath(dbpath=0x00007fff5fbfdf68) + 34 at storage_engine_metadata.cpp:82
    frame #9: 0x0000000100599739 mongod`mongo::ServiceContextMongoD::initializeGlobalStorageEngine(this=0x0000000103719b00) + 89 at service_context_d.cpp:81
    frame #10: 0x00000001000018b9 mongod`mongo::_initAndListen(listenPort=<unavailable>) + 377 at db.cpp:414
    frame #11: 0x0000000100001103 mongod`mongo::initAndListen(listenPort=<unavailable>) + 19 at db.cpp:592
    frame #12: 0x000000010000688c mongod`main [inlined] mongoDbMain(int, char**, char**) + 995 at db.cpp:822
    frame #13: 0x00000001000064a9 mongod`main(argc=<unavailable>, argv=<unavailable>, envp=<unavailable>) + 25 at db.cpp:637
    frame #14: 0x00007fff91a4a5ad libdyld.dylib`start + 1
    frame #15: 0x00007fff91a4a5ad libdyld.dylib`start + 1
(lldb)