Re: [regression?] 2.6.26 floppy boot failure with kernel packed using'upx'

From: H. Peter Anvin
Date: Thu Jul 10 2008 - 13:50:43 EST


Linus Torvalds wrote:

On Thu, 10 Jul 2008, Frans Pop wrote:
Important factor here is that we "pack" the kernel using upx [1] (in order
to fit everything on a floppy). The original (unpacked) kernel after this
commit boots fine, only a packed version fails.
We have tried upx versions 2.01, 3.01 and 3.03, all with same result.

Ok, I do not consider this to be a regression.

Clearly UPX is expecting a very specific kernel format, and clearly UPX just needs to be updated for the changes.

That said, if some UPX person can explain what it is that UPX needs, maybe we can add some format markers into the kernel (and perhaps some extra header info) so that future format changes are transparent or at least break in obvious ways.


The issue with UPX is that UPX actually wants to replace the kernel decompressor, which also does other tasks (relocation and ELF parsing) in recent kernels.

-hpa

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