While testing vector instructions, I ran into various issues with
user space binaries compiled with more recent compiler versions like

# gunzip /usr/share/man/man1/hexdump.1.gz
<dhildenb> *** stack smashing detected ***: <unknown> terminated

Turns out:
a) the STFLE instruction in semi-broken on the first invocation
b) the code expects a different STFLE behavior than documented in the PoP

Fix a) and make sure the code works by adjusting b).

David Hildenbrand (2):
  s390x/tcg: Fix max_byte detection for stfle
  s390x/tcg: Store only the necessary amount of doublewords for STFLE

 target/s390x/misc_helper.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

-- 
2.20.1

On Fri, 31 May 2019 16:56:06 +0200
David Hildenbrand <david@redhat.com> wrote:

> While testing vector instructions, I ran into various issues with
> user space binaries compiled with more recent compiler versions like
> 
> # gunzip /usr/share/man/man1/hexdump.1.gz
> <dhildenb> *** stack smashing detected ***: <unknown> terminated
> 
> Turns out:
> a) the STFLE instruction in semi-broken on the first invocation
> b) the code expects a different STFLE behavior than documented in the PoP
> 
> Fix a) and make sure the code works by adjusting b).
> 

So your problems actually did not have anything to do with vector
instructions and were simply exposed by running binaries compiled with a
more recent compiler version, right? Interesting :)

> David Hildenbrand (2):
>   s390x/tcg: Fix max_byte detection for stfle
>   s390x/tcg: Store only the necessary amount of doublewords for STFLE
> 
>  target/s390x/misc_helper.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 

Do you want to include these in a pull request, or should I pick them
up myself?

On 03.06.19 09:02, Cornelia Huck wrote:
> On Fri, 31 May 2019 16:56:06 +0200
> David Hildenbrand <david@redhat.com> wrote:
> 
>> While testing vector instructions, I ran into various issues with
>> user space binaries compiled with more recent compiler versions like
>>
>> # gunzip /usr/share/man/man1/hexdump.1.gz
>> <dhildenb> *** stack smashing detected ***: <unknown> terminated
>>
>> Turns out:
>> a) the STFLE instruction in semi-broken on the first invocation
>> b) the code expects a different STFLE behavior than documented in the PoP
>>
>> Fix a) and make sure the code works by adjusting b).
>>
> 
> So your problems actually did not have anything to do with vector
> instructions and were simply exposed by running binaries compiled with a
> more recent compiler version, right? Interesting :)

Yes, but it's not the complete story yet. There are still two BUGs
somewhere in emulation code (again, could be !vector register related).
These seem to be harder to track down (e.g., rpm database corruptions
when installing a lot of packages at once).

> 
>> David Hildenbrand (2):
>>   s390x/tcg: Fix max_byte detection for stfle
>>   s390x/tcg: Store only the necessary amount of doublewords for STFLE
>>
>>  target/s390x/misc_helper.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
> 
> Do you want to include these in a pull request, or should I pick them
> up myself?
> 

I can include them.

-- 

Thanks,

David / dhildenb