I am trying to collect a core dump in result of kernel panic. Installed and configured kdump, but when executing echo c > /proc/sysrq-trigger, everything just hangs and the reboot doesn't happen. I don't even get any output in the result of running the command. RAM size is 4GB.

The following is the output of `kdump-config show'

DUMP_MODE:        kdump
USE_KDUMP:        1
KDUMP_SYSCTL:     kernel.panic_on_oops=1
KDUMP_COREDIR:    /var/crash
crashkernel addr: 0x
   /var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinuz-4.9.0-dev
kdump initrd: 
   /var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-4.9.0-dev
current state:    ready to kdump
kexec command:
  /sbin/kexec -p --command-line="BOOT_IMAGE=/boot/vmlinuz-4.9.0-dev root=UUID=b395d695-7bb2-408b-a61b-b5188fc5b900 ro resume=UUID=19e8dc56-ff6d-40de-84ec-b9abd7399591 debug net.ifnames=0 biosdevname=0 ignore_loglevel intel_iommu=on,igfx_off intremap=no_x2apic_optout irqpoll noirqdistrib nr_cpus=1 nousb systemd.unit=kdump-tools.service" --initrd=/var/lib/kdump/initrd.img /var/lib/kdump/vmlinuz

Ubuntu 16.04. Kernel 4.9.0

  • It's probably trying to boot the kdump kernel/initrd and freezing while doing so... To troubleshoot that, you probably need to look at the console attached to the machine to see where it is failing... Is this a machine to which you have physical access to? Or a virtual machine? Or do you somehow have access to a serial console (for example, if it's a server in a colocation)? – filbranden May 15 '18 at 22:56
  • I have a physical access to it – Mr.SrJenea May 15 '18 at 23:11

I had the similar issue on Ubuntu 16.04. This set of commands helped me:

sudo -s
kdump-config load
kdump-config unload

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