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% Registration Kdump, A Kexec based kernel crash dumping
% mechanism
% Vivek Goyal (vgoyal@in.ibm.com)
Kdump is a kexec-based kernel crash dumping
mechanism, which is being perceived as a
reliable crash dumping solution for Linux. In
this paper we discuss what kexec is and what
it can do in general case. Kexec has been
modified to boot a new kernel even in a system
crash event. This paper includes the details
about the changes made in kexec to handle the
panic situations. Given the fact that kexec
enables booting into a new kernel while
preserving the memory contents in a crash
scenario, kdump uses this feature to capture
the kernel crash dump. Physical memory layout
and processor state are encoded in ELF Core
format and these headers are stored in a
reserved section of memory. Upon a crash, new
kernel boots up from reserved memory and
provides a platform to retrieve stored elf
headers and capture the crash dump. We briefly
discuss elf core header creation and dump
capture mechanism and also detail how to
configure and use kdump feature.
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