kdump support in yocto 4 (kernel 5.15.87)

[mabar52]

Hi,

I would like to add support for kdump in our project.

Is the preferred way to use an external crashkernel or already loaded in mem of the primary kernel?

What steps should be undertaken?

what packages do I need to add to the image?

kexec-tools?

makedumpfile?

Kconf?

What of the kexec cmdline?

CPU used: IMX6SX.

Thanks in advance,

Mattias

[mabar52]

Thanks, Joanxie. I have seen this page but it is not clear to me if an external kernel or internal already in mem kernel can be used.
I would prefer internal since I dont want to store an additional crashkernel on FS and flash.

Also what is the ramoops dts config for?
In the pptx it is not specified what kexec -p cmdline is to be used. I guess it also depends on the configuration (internal, external) used?

[joanxie]

I don't know what internal or external you mean, but you can use based on current kernel, ramoops dts config is for enable ramoops/pstore

I guess it also depends on the configuration (internal, external) used?

>Load the second kernel/dump-capture kernel?

[mabar52]

Advancing some as to having kdump started at boot.

But makedumpfle fails with this message, Im afraid:
process_module: dwfl_module_getdwarf error.
init_dwarf_info: Can't get first elf header of /boot/vmlinux-5.15.87-5.15.87-2.2.0+g3f51e675f758.
dwfl_module_getdwarf error.
init_dwarf_info: Can't get first elf header of /boot/vmlinux-5.15.87-5.15.87-2.2.0+g3f51e675f758.
process_module: dwfl_module_getdwarf error.
init_dwarf_info: Can't get first elf header of /boot/vmlinux-5.15.87-5.15.87-2.2.0+g3f51e675f758.
process_module: dwfl_module_getdwarf error.

I added 
IMAGE_INSTALL += "kernel-vmlinux"
To image build.

[mabar52]

Anyidea as to how use makedumpfile without a working vmlinux?

[mabar52 · Accepted solution]

We will work with only the dmesg portion from the vmcore as for now. 
(MAKEDUMPFILE_ARGS="--dump-dmesg").

It now works and its ok as a first iteration with kdump so that we can at least see why the kernel crashed in dmesg.

[joanxie]

pls refer to the link as below:

"https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Kdump-Crash-in-I-MX/ta-p/1124321"