Re: [Crash-utility] The problems when running SuSE 12 on VirtualBox

----- Original Message ----- > I can see the crash will use "/proc/kcore" instead of "/dev/mem". So I > try the same thing on VirtualBox: > > # crash /boot/vmlinux-3.12.49-6-xen.gz /proc/kcore > > crash 7.1.3 > Copyright (C) 2002-2014 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 <http://gnu.org/licenses/gpl.html> > 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"... > > KERNEL: /boot/vmlinux-3.12.49-6-xen.gz > DEBUGINFO: /usr/lib/debug/boot/vmlinux-3.12.49-6-xen.debug > DUMPFILE: /proc/kcore > CPUS: 1 > DATE: Thu Nov 19 01:53:01 2015 > UPTIME: 05:42:13 > LOAD AVERAGE: 0.19, 0.06, 0.06 > TASKS: 239 > NODENAME: linux-6ev3 > RELEASE: 3.12.49-6-xen > VERSION: #1 SMP Mon Oct 26 16:05:37 UTC 2015 (11560c3) > MACHINE: x86_64 (2594 Mhz) > MEMORY: 855.2 MB > PID: 3106 > COMMAND: "crash" > TASK: ffff88002ec5c040 [THREAD_INFO: ffff88000b3e2000] > CPU: 0 > STATE: TASK_RUNNING (ACTIVE) > > crash> > > It seems OK now. > > So my questions are: > > (1) Is it OK to use "/proc/kcore" instead of "/dev/mem" as a workaround? > Is there any side-effect? Yes /proc/kcore is fine, and it's not really a "workaround". Since your kernel was configured with CONFIG_STRICT_DEVMEM, /dev/mem is unusable because it does not allow reads above 1MB physical. And so as you saw above on the physical machine, crash then tries to use /proc/kcore as an alternative, and it worked OK.