Kernel dump file access library (repost)

Atsushi Kumagai kumagai-atsushi at
Thu Nov 27 00:09:57 PST 2014

Hello Petr,

>Hi all,
>during this year's SUSE HackWeek, my colleague started work on enabling
>kernel core files in gdb. I realized that there would be at least four
>different programs implementing read access to kernel dump files:
>  1. the crash utility
>  2. makedumpfile (when re-filtering)
>  3. kdumpid (my project to get kernel version from a dump file)
>  4. gdb-kdump (started by my colleague during HackWeek)
>At this point, I felt that's too much re-inventing the wheel again and
>again, so I took my current code from kdumpid and adapted it as a
>library that can be used by everybody:

I agree with you, your idea sounds reasonable.

>In its current shape, it's usable, but far from complete.
>Things that work already:
>   - identify kdump file format
>   - parsed meta-information from the header
>   - open ELF, diskdump, makedumpfile, LKCD
>   - read data by physical address (incl. Xen Dom0)
>   - read data by Xen machine address
>Things still on my TODO list:
>   - more formats: sadump, kvmdump, libvirt, xc_core, xc_save
>   - determine phys_base in ELF files
>   - determine kernel release if not found in headers

Aren't you going to make writer methods ?
If makedumpfile uses the library, I want to get rid of the dump format
specific codes completely from makedumpfile, otherwise "re-inventing"
will still occur.
I suppose that other tools don't need writer methods, so I think
it would be better if I make them.

>Ideally, I would like to replace all current implementations with this
>library, so if a new file format appears, or a new feature is added to
>one of the files, it can be immediately used by all kdump-related tools.
>Please let me know what you think.
>Oh, and if you're developing such a tool, let me know which features
>should be added.

I've started an experiment to find out practical problems in switching
to using the library. I'll let you know if I find any problems.

Atsushi Kumagai

>Petr Tesarik
>Crash-utility mailing list
>Crash-utility at

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