On 11/19/2015 07:45 AM, Dave Anderson wrote: > ----- 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. These things I believe to be the case: The SUSE kernel is CONFIG_STRICT_DEVMEM for UEFI Secure Boot not Xen in particular. There's also the crash.ko module which should allow /dev/crash to be used instead of either /dev/mem or /proc/kcore but it's not loaded by default on SUSE installations. -- David. -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
