Kdump, A Kexec based kernel crash dumping mechanism

Kdump is 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.