These all occurred when sent a SIGTERM signal to mongo process (to gracefully terminate the instance):

Example 1:

Fri Dec 3 15:28:33 [initandlisten] shutdown: going to flush oplog...
Fri Dec 3 15:28:33 [initandlisten] shutdown: going to close sockets...
Fri Dec 3 15:28:33 [initandlisten] shutdown: waiting for fs preallocator...
Fri Dec 3 15:28:33 [initandlisten] shutdown: closing all files...
Fri Dec 3 15:28:33 [conn1] end connection 127.0.0.1:58246
Fri Dec 3 15:28:33 [interruptThread] now exiting
Fri Dec 3 15:28:33 dbexit: ; exiting immediately
mongod: /opt/boost/include/boost/thread/pthread/mutex.hpp:50: void boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed.
Fri Dec 3 15:28:33 Got signal: 6 (Aborted).

Example 2:

Mon Dec 6 09:04:55 [initandlisten] shutdown: going to flush oplog...
Mon Dec 6 09:04:55 [initandlisten] shutdown: going to close sockets...
Mon Dec 6 09:04:55 [initandlisten] shutdown: waiting for fs preallocator...
Mon Dec 6 09:04:55 [initandlisten] shutdown: closing all files...
Mon Dec 6 09:04:55 [interruptThread] now exiting
Mon Dec 6 09:04:55 dbexit: ; exiting immediately
Mon Dec 6 09:04:55 Got signal: 11 (Segmentation fault).

Example 3:

• • • glibc detected *** /home/at/ats/ats-tools/mongodb/current/bin/mongod: double free or corruption (fasttop): 0x0a16c9b0 ***