----- Original Message ----- > 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. Hmmm. I've never tried it, but because of the relocation, live access won't work. But you *may* be able to coerce it into coming up by forcing the phys_base to whatever it is: # crash --machdep phys_base=<physical-base-address> BTW, that's with x86_64 only. Dave > > 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@xxxxxxx > (651) 683-3824 > > -- > Crash-utility mailing list > Crash-utility@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/crash-utility -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
