Why is crash command exiting without prompt?

I've installed a debug kernel and enabled kdump. The coredump was generated successfully, but when I try to load the vmcore after reboot, crash command just quit without prompt: # crash /usr/lib/debug/usr/lib/modules/3.10.0-693.11.6.el7.x86_64.debug/vmlinux /var/crash/127.0.0.1-2019-05-25-22\:55\:50/vmcore crash 7.2.3-8.el7 Copyright (C) 2002-2017 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005, 2011 NEC Corporation Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. This program is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Enter "help copying" to see the conditions. This program has absolutely no warranty. Enter "help warranty" for details. GNU gdb (GDB) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. 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-unknown-linux-gnu"... Any ideas? Is there any way to convert vmcore file to a coredump file so that I can load it directly with gdb?