Hello,

Michael Kelly, le mer. 22 juil. 2026 08:23:07 +0100, a ecrit:
> On 18/07/2026 22:13, Samuel Thibault wrote:
> > Re,
> > 
> > Michael Kelly, le sam. 18 juil. 2026 21:35:50 +0100, a ecrit:
> > > The corruptions that we have seen often follow the pattern having 16
> > > bytes of zero at offsets 0x50, 0x70 and 0xff0 in 1 or more pages in
> > > the file.
> > And I haven't seen such kind of corruptions in other builds, so that
> > leads me to believe this is really related to ghc's particular habit of
> > frequent timer signals.
> 
> Thanks for the details regarding the buildd configuration etc. I have
> reconfigured my VM using 2Mb huge pages and will attempt the same on my
> other machine using 1Gb pages when I bring it back home at the weekend. This
> was the most notable difference that I could see in my setup.
> 
> It hasn't shown any of the corruption to the locally built libraries yet
> though.

Uh :/

> The repeated build has however shown one result which could
> potentially be valuable in that haskell-attoparsec fails its build tests
> approximately 10% of the time running the test case described as 't_iter':

But it does so on i386 too.

> It might of course be totally unconnected to the corruption

Yes, it's very probably unconnected.

I asked chatgpt about the pattern, it mentioned it could be some page
management by ghc itself, like clearing a couple of fields and an
end-of-page marker. It's odd that it's 16 bytes for all three of these,
though.

Samuel

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