I wrote a go-language mongodb client to use mongodb data, if I kill my client process, I found that mongodb entered dead-loop state. I used htop to see what happens:

PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command
1211 root 20 0 1395M 138M 97656 S 100. 1.8 1h16:10 /root/mongodb/bin/mongod -f /home/hunter/hunterServer/rundir/conf/mongodb.conf -fork
347 root 20 0 1395M 138M 97656 R 100. 1.8 1h10:24 /root/mongodb/bin/mongod -f /home/hunter/hunterServer/rundir/conf/mongodb.conf -fork

It looked that the thread(PID:347) of mongod process(PID:1211) occupy 100% CPU, I tried use mongostat, mongotop to figure out which operation there, but no any operation in mongodb.

I used pstack 347, it looked that mongod enter a dead-loop because the following unhandled exception.

[root@hkDEV6 ~]# pstack 347
Thread 1 (process 347):
#0 0x00007f2fb3ab5547 in ?? () from /lib64/libgcc_s.so.1
#1 0x00007f2fb38263d6 in dl_iterate_phdr () from /lib64/libc.so.6
#2 0x00007f2fb3ab6207 in _Unwind_Find_FDE () from /lib64/libgcc_s.so.1
#3 0x00007f2fb3ab3603 in ?? () from /lib64/libgcc_s.so.1
#4 0x00007f2fb3ab46a6 in _Unwind_RaiseException () from /lib64/libgcc_s.so.1
#5 0x00007f2fb3ffad15 in __cxa_throw () from /usr/lib64/libstdc++.so.6
#6 0x00000000011ba4cd in mongo::Socket::handleRecvError(int, int) ()
#7 0x00000000011bae44 in mongo::Socket::_recv(char*, int) ()
#8 0x00000000011bae59 in mongo::Socket::unsafe_recv(char*, int) ()
#9 0x00000000011baea5 in mongo::Socket::recv(char*, int) ()
#10 0x00000000011af94c in mongo::MessagingPort::recv(mongo::Message&) ()
#11 0x00000000011b28a8 in mongo::PortMessageServer::handleIncomingMsg(void*) ()
#12 0x00007f2fb44539d1 in start_thread () from /lib64/libpthread.so.0
#13 0x00007f2fb37effbd in clone () from /lib64/libc.so.6