So I was having an issue with rsyslog in one of my CentOS 6.6 hosts:

[root@scan ~]# /etc/init.d/rsyslog start Starting system logger: *** glibc detected *** /sbin/rsyslogd: double free or corruption (fasttop): 0x00007f80cc3da880 ***
======= Backtrace: ========/lib64/libc.so.6(+0x75e66)[0x7f80c9210e66]
/usr/lib64/librelp.so.0(relpTcpDestruct+0x5f)[0x7f80c7f1a9bf]
/usr/lib64/librelp.so.0(relpSrvRun+0x4c)[0x7f80c7f1d08c]
/usr/lib64/librelp.so.0(relpEngineListnerConstructFinalize+0x26)[0x7f80c7f16ac6]
/usr/lib64/librelp.so.0(relpEngineAddListner+0x91)[0x7f80c7f16c61]
/lib64/rsyslog/imrelp.so(+0xd4c)[0x7f80c8122d4c]
[…]
7fff6c305000-7fff6c31c000 rw-p 00000000 00:00 0 [stack]
7fff6c3ff000-7fff6c400000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0
[vsyscall]

^C
[root@scan ~]#

Since this is the only machine I put relp in (I was playing with it), and all the others are working, I decided to remove rsyslog-relp-5.8.10-10.el6_6.x86_64 to see if that solves the issue. So, I

yum remove rsyslog-relp

and restarted rsyslog and it works now. Now that is fixed, what would cause rsyslog-relp to crash rsyslog?