Re: [PATCH 1/2] boot: increase stack size for kernel boot loaderdecompressor

From: Ingo Molnar
Date: Tue Apr 08 2008 - 04:24:23 EST



* Alexander van Heukelum <heukelum@xxxxxxxxxxxxx> wrote:

> I did see that the malloc space that the inflate code is using is
> taken from _after_ the end of the bss. I don't see how this is
> protected from being used/overwritten. Changing the stack size changes
> the memory layout a bit... maybe you were so unlucky to create a
> vmlinux image that was just barely smaller than some threshold and
> increasing the stack size made the decompression/relocation area be
> located somewhere else?
>
> Test patch follows.

that's a really interesting theory.

FWIIW, i've been booting allyesconfig bzImages for a long time (with
only minimal amount of drivers disabled - mostly old ISA ones that
assume the presence of the real hardware), and they boot and work fine
on both 32-bit and 64-bit typical whitebox PCs. That means huge bzImages
that decompresses into a ~41 MB kernel image. I'd expect that to be a
rather severe test of the decompressor.

Ingo
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