Re: [Bug 1847232] [NEW] qemu TCG in s390x mode issue with calculating HASH

[David Hildenbrand <david@redhat.com>]

On 08.10.19 16:11, Ivan Warren wrote:
> 
> On 10/8/2019 3:35 PM, David Hildenbrand wrote:
>> On 08.10.19 14:11, Cornelia Huck wrote:
>>> On Tue, 08 Oct 2019 11:19:25 -0000
>>> Ivan Warren via <qemu-devel@nongnu.org> wrote:
>>>
>>>> Public bug reported:
>>>>
>>>> When using go on s390x on Debian x64 (buster) (host) and debian s390x
>>>> (sid) (guest) I run into the following problem :
>>>>
>>>> The following occurs while trying to build a custom project :
>>>>
>>>> go: github.com/FactomProject/basen@v0.0.0-20150613233007-fe3947df716e:
>>>> Get
>>>> https://proxy.golang.org/github.com/%21factom%21project/basen/@v/v0.0.0-20150613233007-fe3947df716e.mod:
>>>> local error: tls: bad record MAC
>>>>
>>>> Doing a git bisect I find that this problem only occurs on and after
>>>> commit 08ef92d556c584c7faf594ff3af46df456276e1b
>>>>
>>>> Before that commit, all works fine. Past this commit, build always
>>>> fails.
>>> What version are you using? Current master?
>>>
>>> Can you please share your command line?
>>>
>>>> Without any proof, It looks like a hash calculation bug related to using
>>>> z/Arch vector facilities...
>>> Not an unreasonable guess, cc:ing David in case he has seen that before.
>>>
>> Can you reproduce with "-cpu qemu,vx=off" added to the QEMU command
>> line? Could be some fallout from vector instruction support. Currently
>> ill, will have a look when I'm feeling better.
> 
> Reposted with a reply all... (sorry for the duplicates)
> 
> So it does !
> 
> 
> My qemu command line is now (forget the odd funny networking things..)
> 
> qemu-system-s390x \
>       -drive
> file=DEB002.IMG.NEW,discard=unmap,cache=writeback,id=drive-0,if=none \
>       -device virtio-scsi-ccw,id=virtio-scsi-0 \
>       -device scsi-hd,id=scsi-hd-0,drive=drive-0 \
>       -m 8G \
>       -net nic,macaddr=52:54:00:00:00:02 \
>       -net tap,ifname=taparm,script=no \
>       -nographic -accel tcg,thread=multi \
>       -monitor unix:ms,server,nowait \
>       -cpu qemu,vx=off \  ##### THAT WAS ADDED as instructed - without it
> everything goes kaput !
>       -smp 12
> 
> And using the latest bleeding edge qemu from github, my build works (the
> problem goes away).
> 
> So the z/Arch vector instructions may have a glitch is a venue to
> consider.. Probably one that couldn't be screened through conventional
> methods.
> 
> I'm not that versed into z/Arch vector instruction, but if there
> anything I can help with, I will !

I'll have to reproduce, can you outline the steps needed to trigger 
this? (never had to build a go project before #luckyme ( ;) )). It looks 
like https://github.com/FactomProject/basen is getting pulled in from 
some other project?

Thanks!


-- 

Thanks,

David / dhildenb