Шаги для воспроизведения:

В первой консоли выполнить команду: 
# dhcpcd -N eth0 --nobackground
sending signal USR1 to pid 6266
eth0: rebinding lease of 10.88.9.122
eth0: leased 10.88.9.122 for 24379 seconds
eth0: changing route to 10.88.8.0/21
eth0: changing default route via 10.88.8.1

Затем, во второй консоли выполнить команду:
# dhcpcd -N eth0 
sending signal USR1 to pid 6291

Результат:
Вывод в консоли, где запущена первая команда:
received SIGUSR1, renewing
Ошибка сегментирования

Примечание:
Воспроизводится в Р8 (dhcpcd-6.11.5.alt1). В Сизифе не воспроизводится (dhcpcd-7.2.1-alt1).

Дополнительная информация. Отладка в GDB:
[root@work-8-2-x86-64-default ~]# gdb dhcpcd
GNU gdb (GDB) 7.9-alt3 (ALT Linux)
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-alt-linux".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from dhcpcd...Reading symbols from /usr/lib/debug/sbin/dhcpcd.debug...done.
done.
(gdb) run -N eth0 --nobackground
Starting program: /sbin/dhcpcd -N eth0 --nobackground
sending signal USR1 to pid 2495
Detaching after fork from child process 2652.
Detaching after fork from child process 2653.
eth0: rebinding lease of 10.88.9.24
eth0: leased 10.88.9.24 for 24551 seconds
eth0: changing route to 10.88.8.0/21
eth0: adding default route via 10.88.8.1
Detaching after fork from child process 2654.

Program received signal SIGUSR1, User defined signal 1.
0x00007ffff7b1e550 in __GI_epoll_pwait (epfd=3, events=events@entry=0x7fffffffe0d0, 
    maxevents=maxevents@entry=1, timeout=12274970, set=set@entry=0x7fffffffe230)
    at ../sysdeps/unix/sysv/linux/epoll_pwait.c:42
42	  return SYSCALL_CANCEL (epoll_pwait, epfd, events, maxevents,
(gdb) c
Continuing.
received SIGUSR1, renewing

Program received signal SIGSEGV, Segmentation fault.
0x0000000000406177 in dhcpcd_ifrenew (ifp=0x659080) at dhcpcd.c:1187
1187		if (ifp->options->options & DHCPCD_LINK &&
(gdb) bt
#0  0x0000000000406177 in dhcpcd_ifrenew (ifp=0x659080) at dhcpcd.c:1187
#1  dhcpcd_renew (ctx=<optimized out>) at dhcpcd.c:1203
#2  0x0000000000408e01 in eloop_start (eloop=0x658a90, signals=signals@entry=0x7fffffffe230)
    at eloop.c:866
#3  0x000000000040395e in main (argc=<optimized out>, argv=<optimized out>) at dhcpcd.c:1940
(gdb) l
1182	static void
1183	dhcpcd_ifrenew(struct interface *ifp)
1184	{
1185	
1186	#define DHCPCD_RARENEW (DHCPCD_IPV6 | DHCPCD_IPV6RS)
1187		if (ifp->options->options & DHCPCD_LINK &&
1188		    ifp->carrier != LINK_DOWN)
1189		{
1190			dhcp_renew(ifp);
1191			if ((ifp->options->options & DHCPCD_RARENEW) == DHCPCD_RARENEW)
(gdb) print ifp
$1 = (struct interface *) 0x659080
(gdb) print ifp->options
$2 = (struct if_options *) 0x0
(gdb) print *ifp
$3 = {ctx = 0x7fffffffe150, next = {tqe_next = 0x0, tqe_prev = 0x658f68}, 
  name = "lo", '\000' <repeats 13 times>, index = 1, active = 0, flags = 65609, family = 772, 
  hwaddr = '\000' <repeats 19 times>, hwlen = 6 '\006', metric = 201, carrier = 0, wireless = 0, 
  ssid = '\000' <repeats 32 times>, ssid_len = 0, profile = '\000' <repeats 63 times>, options = 0x0, 
  if_data = {0x660e80, 0x0, 0x0, 0x0, 0x659290, 0x0, 0x0}}
(gdb)