Hi ,

kdump need 2 kernel primary and secondary. Primary will be panicked, then secondary will do capture coredump. 

In boot loader/ kernel command line specify crashkernel=256MB or more, ensure secondary kernel is small in size so that it can be boot within this memory, oom should not happen. 

Primary config:
CONFIG_SYSFS=y
CONFIG_KEXEC=y
CONFIG_DEBUG_INFO=y

Secondary Config:
CONFIG_PHYSICAL_START=0x100000
CONFIG_RELOCATABLE=y
CONFIG_CRASH_DUMP=y

load secondary kernel using 
kexec -p  <>

After kernel panic, secondary kernel will be invoked. The secondary kernel should save core from /proc/vmcore  and reboot again. 

Refer kdump kernel docs : https://www.kernel.org/doc/Documentation/kdump/kdump.txt 

Thanks,
Satya  

On Fri, May 15, 2020 at 11:17 PM 慕冬亮 <mudongliangabcd@gmail.com> wrote:


On May 15, 2020, at 12:47 PM, Subhashini Rao Beerisetty <subhashbeerisetty@gmail.com> wrote:

Hi all,

In  Kernel, what needs to be configured to get the crash dump?
Can someone clarify me with the sequence of steps to get the crash dump..


Some materials for specific Linux distributions(e.g., Redhat, Debian):



https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/kernel_administration_guide/kernel_crash_dump_guide

https://fedoraproject.org/wiki/How_to_use_kdump_to_debug_kernel_crashes



Thanks,

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