multipathd segfault on shutdown or restart in RHEL 6

Issue

• We're seeing this message on 'service multipathd restart',

multipathd[8763]: segfault at 18 ip 00007f5f18be1155 sp 00007fff43713ee0 error 4 in libc-2.12.so[7f5f18b6c000+197000]

• multipathd segfaults when restarting or stopping the daemon, with the following backtrace seen in the core:

(gdb) bt
#0  0x00007fe75657e155 in malloc_consolidate (av=0x7fe7568a5e80) at malloc.c:5169
#1  0x00007fe7565811c2 in _int_malloc (av=0x7fe7568a5e80, bytes=<value optimized out>) at malloc.c:4373
#2  0x00007fe756582288 in __libc_calloc (n=<value optimized out>, elem_size=<value optimized out>)
    at malloc.c:4065
#3  0x00007fe75657719d in open_memstream (bufloc=0x7fffed633290, sizeloc=0x7fffed633288) at memstream.c:86
#4  0x00007fe7565eabbb in __vsyslog_chk (pri=29, flag=-1, fmt=0x7fe7568ea36d "%s", ap=0x7fffed6332e0)
    at ../misc/syslog.c:169
#5  0x00007fe7565eb230 in __syslog (pri=<value optimized out>, fmt=<value optimized out>)
    at ../misc/syslog.c:119
#6  0x00007fe7568df460 in log_syslog (buff=0xab0240) at log.c:194
#7  0x00007fe7568debec in flush_logqueue () at log_pthread.c:43
#8  0x00007fe7568dedad in log_thread_stop () at log_pthread.c:92
#9  0x0000000000408ee6 in child (param=0x0) at main.c:1592
#10 0x00000000004094a4 in main (argc=1, argv=0x7fffed6336d8) at main.c:1741