Saw this after ctrl-c'ing mongod after doing some testing:

Wed Dec 14 18:56:53 dbexit: really exiting now
Logstream::get called in uninitialized state
Wed Dec 14 18:56:53 [journal] exception in dur::groupCommitLL causing immediate shutdown: boost::lock_error
Wed Dec 14 18:56:53 dur4
Wed Dec 14 18:56:53 Got signal: 6 (Abort trap: 6).

Wed Dec 14 18:56:53 Backtrace:
0x104dd1e15 0x10555a78e 0x7fff8b3bccfa 0 0x7fff8b35ba7a 0x1052e8a3e 0x105166c1d 0x10516837a 0x10516557e 0x10556f7d1 0x106f97460 0x7fff8b3688bf 0x7fff8b36bb75
0 mongod 0x0000000104dd1e15 _ZN5mongo15printStackTraceERSo + 37
1 mongod 0x000000010555a78e _ZN5mongo10abruptQuitEi + 446
2 libsystem_c.dylib 0x00007fff8b3bccfa _sigtramp + 26
3 ??? 0x0000000000000000 0x0 + 0
4 libsystem_c.dylib 0x00007fff8b35ba7a abort + 143
5 mongod 0x00000001052e8a3e _ZN5mongo10mongoAbortEPKc + 190
6 mongod 0x0000000105166c1d _ZN5mongo3dur27groupCommitWithLimitedLocksEv + 1421
7 mongod 0x000000010516837a _ZN5mongo3durL2goEv + 154
8 mongod 0x000000010516557e _ZN5mongo3dur9durThreadEv + 718
9 mongod 0x000000010556f7d1 _ZN5boost6detail11thread_dataIPFvvEE3runEv + 25
10 libboost_thread-mt.dylib 0x0000000106f97460 thread_proxy + 160
11 libsystem_c.dylib 0x00007fff8b3688bf _pthread_start + 335
12 libsystem_c.dylib 0x00007fff8b36bb75 thread_start + 13