On Linux/x86-64, I got

[root@gnu-9 hjl]# /usr/sbin/glibc_post_upgrade.x86_64
/usr/sbin/glibc_post_upgrade: While trying to execute /sbin/service child exited with exit code 1
[root@gnu-9 hjl]# 

with glibc-2.13.90-14.  The problem is

  if (check_elf ("/proc/1/exe"))
    verbose_exec (116, "/sbin/telinit", "/sbin/telinit", "u");

  /* Check if we can safely condrestart sshd.  */
  if (access ("/sbin/service", X_OK) == 0
      && access ("/usr/sbin/sshd", X_OK) == 0
      && access ("/etc/rc.d/init.d/sshd", X_OK) == 0
      && access ("/bin/bash", X_OK) == 0)
    {
      if (check_elf ("/usr/sbin/sshd"))
        verbose_exec (-121, "/sbin/service", "/sbin/service", "sshd", "condrestart");
    }

in glibc_post_upgrade.c. It can be reproduced with:

[root@gnu-snb-1 hjl]# /sbin/telinit u; /sbin/service sshd condrestart
Restarting sshd (via systemctl):  Failed to get D-Bus connection: Connection terminated during authentication.
                                                           [FAILED]

Add a sleep works:

[root@gnu-snb-1 hjl]# /sbin/telinit u; sleep 1; /sbin/service sshd condrestart
Restarting sshd (via systemctl):                           [  OK  ]
[root@gnu-snb-1 hjl]#