Re: data corruption with nvidia chipsets and IDE/SATA drives // memory hole mapping related bug?!

[Christoph Anton Mitterer <calestyo@scientia.net>]

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Karsten Weiss wrote:
> Here's a diff of a corrupted and a good file written during our
> testcase:
>
> ("-" == corrupted file, "+" == good file)
> ...
>   009f2ff0  67 2a 4c c4 6d 9d 34 44  ad e6 3c 45 05 9a 4d c4  |g*L.m.4D..<E..M.|
> -009f3000  39 60 e6 44 20 ab 46 44  56 aa 46 44 c2 35 e6 44  |9.D .FDV.FD.5.D|
> ....
> +009f3ff0  f3 55 92 44 c1 10 6c 45  5e 12 a0 c3 60 31 93 44  |.U.D..lE^...1.D|
>   009f4000  88 cd 6b 45 c1 6d cd c3  00 a5 8b 44 f2 ac 6b 45  |..kE.m.....D..kE|
>   
Well as I told in my mails to the list I made the experience that not
all bytes of the corrupted area are invalid,.. but only some,.. while it
seems that in you diff ALL the bytes are wrong, right?


> Please notice:
>
> a) the corruption begins at a page boundary
> b) the corrupted byte range is a single memory page and
> c) almost every fourth byte is set to 0x44 in the corrupted case
>     (but the other bytes changed, too)
>
> To me this looks as if a wrong memory page got written into the
> file.
>   
Hmm and do you have any ideas what's the reason for all this? Defect in
the nforce chipset? Or even in the CPU (the Opterons do have integrated
memory controllers).


> >From our testing I can also tell that the data corruption does
> *not* appear at all when we are booting the nodes with mem=2G.
> However, when we are using all the 4GB the data corruption
> shows up - but not everytime and thus not on all nodes.
> Sometimes a node runs for ours without any problem. That's why
> we are testing on 32 nodes in parallel most of the time. I have
> the impression that it has something to do with physical memory
> layout of the running processes.
>   
Hmm maybe,.. but I have absolutely no idea ;)


> Please also notice that this is a silent data corruption. I.e.
> there are no error or warning messages in the kernel log or the
> mce log at all.
>   
Yes I can confirm that.


> Christoph, I will carefully re-read your entire posting and the
> included links on Monday and will also try the memory hole
> setting.
>   
And did you get out anything new?

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