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Re: Hidden timeskew problems might show up on 2.6.x kernels



On Tue, Jan 13, 2004 at 09:32:40PM +0100, Jeroen van Wolffelaar wrote:
> Hi,
> 
> After quite a while being puzzled why my package, building fine on my
> computer, failed to be build by my sponsor. Everything indicated
> automake was being run, while it shouldn't.
> 
> It turned out, that 2.6.x kernels support mtimes of high precision
> (nanoseconds rather than just seconds). Since in the diff file, the
> Makefile.in was patched before the Makefile.am, the .am got a newer
> mtime, and caused automake to be invoked. Swapping them around in the
> diff solved this. On my 2.4.x kernel, this didn't happen, because both
> were patched in the same second, but it always happened on my sponsor's
> machine...
> 
> The issue here is, that it is very well possible that there are source
> packages in the archive, which were never build by 2.6.x kernels, and
> thus might very well contain the same miniscule timeskew problem.

Ah, the irony. This is an old problem, already known by us m68k
maintainers. Until now, this issue has been dismissed by some as "not
likely to hit real architectures anyway", so I'm actually quite happy
that this is happening on 2.6 kernels too, now :)
</sarcasm>

All this just to say that it shouldn't really matter much. Most of the
packages that could be vulnerable to this already hit that problem due
to the fact that they've been built on a buildd on one of the slower
architectures in the past.

Possible ways to adequately fix this problem have been documented in the
README.Debian file of the "autotools-dev" package, under the header "The
problem with timestamp skews and Debian source packages".

-- 
Wouter Verhelst
Debian GNU/Linux -- http://www.debian.org
Nederlandstalige Linux-documentatie -- http://nl.linux.org
"Stop breathing down my neck." "My breathing is merely a simulation."
"So is my neck, stop it anyway!"
  -- Voyager's EMH versus the Prometheus' EMH, stardate 51462.



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