White Paper: Red Hat Crash Utility


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Prerequisites

The crash utility has the following prerequisites:

kernel object file:

A vmlinux kernel object file, often referred to as the namelist in this document, which must have been built with the -g C flag so that it will contain the debug data required for symbolic debugging. The vmlinux file associated with the running kernel is typically found in the /boot directory; it will have the operating system release string appended to it, for example, vmlinux-2.4.21-4.ELsmp.

Ideally the kernel object file is the same kernel object file that is associated with the memory image. However, in circumstances where the vmlinux file associated with the crash dump or live system was not built with the -g flag, there are work-arounds discussed later in the Invocation section.


memory image:

This may consist of a kernel crash dump file generated from any of the three crash dump facilities (Red Hat Netdump, Mission Critical Linux Mcore, or LKCD), or live system memory accessed via /dev/mem. If no dump file argument is issued on the crash command line, live system memory will be used by default. When examining a live system, root privileges are required.

Support for the Red Hat Netdump dumpfile format is actively maintained and supported. Support for the Mcore dumpfiles exists only because the kernel patch that creates them is no longer being updated or maintained. Support for 2.4-based LKCD dumpfiles exists on an as-is basis, and is not actively maintained. However, if LKCD eventually becomes part of the mainstream kernel in the future, maintenance will be resumed.


platform processor types:

The crash utility is actively developed and tested on Intel x86 and IA64 processors. Legacy support for the Alpha and 32-bit PowerPC platforms exists, but no longer actively maintained. Support for the AMD64, PPC64, s390 and s390x processors are targetted for future support.

Linux kernel versions:

The crash utility is backwards-compatible to at least Red Hat 6.0 (Linux version 2.2.5-15), up to Red Hat Enterprise Linux 3 (Linux version 2.4.21+). The intent has always been to make the utility independent of Linux version dependencies, building in recognition of major kernel code changes so as to adapt to new kernel versions, while maintaining backwards compatibility.



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