Actually, it only segv's on x86_64 and ia64, but the search for the booted System.map file fails quietly for all but s390 and s390x. VTOP() used to be a simple masking of the kernel virtual address, but over time, the base kernel virtual addresses can vary, and the base address determination has not happened this early in the crash session. So I'm going to change it such that a more useful error message gets printed, and then a graceful exit, like this: # crash vmlinux-2.6.18-8.el5 crash 4.0-4.3rc1 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Red Hat, Inc. Copyright (C) 2004, 2005, 2006 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005 NEC Corporation Copyright (C) 1999, 2002 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. WARNING: vmlinux-2.6.18-8.el5 and /proc/version do not match! WARNING: /proc/version indicates kernel version: 2.6.18-8.1.3.el5 crash: please use the vmlinux file for that kernel version, or try using the System.map for that kernel version as an additional argument. # Now obviously the best remedy is to use the correct vmlinux file. But if it's not available, and the non-matching vmlinux file is "close enough", then the System.map suggestion may work. Taking the example above, it works like so: # crash vmlinux-2.6.18-8.el5 /boot/System.map-2.6.18-8.1.3.el5 crash 4.0-4.3rc1 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Red Hat, Inc. Copyright (C) 2004, 2005, 2006 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005 NEC Corporation Copyright (C) 1999, 2002 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 6.1 Copyright 2004 Free Software Foundation, Inc. GDB 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. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "ia64-unknown-linux-gnu"... please wait... (patching 27218 gdb minimal_symbol values) SYSTEM MAP: /boot/System.map-2.6.18-8.1.3.el5 DEBUG KERNEL: vmlinux-2.6.18-8.el5 (2.6.18-8.el5) DUMPFILE: /dev/mem CPUS: 2 DATE: Wed Jun 13 15:42:55 2007 UPTIME: 5 days, 15:12:08 LOAD AVERAGE: 1.10, 1.04, 1.05 TASKS: 123 NODENAME: hp-rx2660-01.lab.boston.redhat.com RELEASE: 2.6.18-8.1.3.el5 VERSION: #1 SMP Mon Apr 16 15:55:02 EDT 2007 MACHINE: ia64 (1594 Mhz) MEMORY: 16 GB PID: 29467 COMMAND: "crash" TASK: e00000012f2e8000 [THREAD_INFO: e00000012f2e9040] CPU: 0 STATE: TASK_RUNNING (ACTIVE) crash> Dave