"echo c > /proc/sysrq-trigger" generates the kernel dump but it
reboots the system.
I'd like to generate kernel dump without system reboot.

I think it is possible to jump to the kdump kernel and generate kernel
dump, and come back to the operating kernel with kexec.
I know I can jump to the kdump kernel with "kexec -e" but I cannot
figure out how to come back to the operating kernel.

For example, I tried following sequences after reading kexec manual page.

0. rebuild kernel with CONFIG_KEXEC_JUMP option
1. kexec --load=/boot/vmlinuz --initrd=/boot/initrd --reuse-cmdline
2. kexec -e
3. now kdump kernel is running
4. kexec --load-jump-back-helper --entry=<ADDRESS>
5. kexec -e

I can jump to the kdump kernel with step 1 and step 2.
kexec manual says I need an entry address.
I don't know what address I should use.
I found a email thread about jump_back_entry= but there is no
parameter like jump_back_entry in kernel booting parameters of

Does anybody know how to use kexec to jump between kdump kernel and
operating kernel?


Best regards,
Gioh Kim

kexec mailing list

Reply via email to