Re: [Crash-utility] How do debug the kdump kernel using a Xen dump-core file?

Hi Olaf, On Thu, Feb 10, 2011 at 02:07:02PM +0100, Olaf Hering wrote: > > Hello, > > 'xm dump-core -L <domain>' generates a coredump of a Xen4 HVM guest, and > crash is able to poke around in this coredump. > Thanks for that. > > But: How can I use crash to debug the crash/kdump kernel itself? > I did a 'echo c > /proc/sysrq-trigger' and want to look at the crash > kernel, not the normal kernel. > > Olaf You can make the crash kernel come all the way up to multi-user mode. Then run crash. I haven't run crash under the crash kernel, but I don't see why it wouldn't work.

I use this method with a SLES system: edit /etc/sysconfig/kdump and set KDUMP_SAVEDIR to a non-existing dir: KDUMP_SAVEDIR="file:///fubar" KDUMP_IMMEDIATE_REBOOT="no" Or this seems to work with a RHEL6 system: - edit /etc/init.d/kdump and comment out the makedumpfile and restart lines; just make it exit - modify script /sbin/mkdumprd so that it does not save a dump, but goes to user mode: 2429,2430c2429,2432 < emit " $CORE_COLLECTOR /proc/vmcore \$VMCORE-incomplete... > emit "# $CORE_COLLECTOR /proc/vmcore > \$VMCORE-incomplete... --- < emit " exitcode=\$?" > emit " exitcode=1" 2444c2446,2448 < emit " $FINAL_ACTION" > emit " echo bye" and /etc/init.d/kdump to not call save_core in the crash kernel: start) if [ -s /proc/vmcoreXXX ]; then save_core ) -Cliff -- Cliff Wickman SGI cpw(a)sgi.com (651) 683-3824 -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility