Wine and Valgrind / handling SIGILL

[Austin English]

On Thu, Jan 19, 2017 at 9:40 PM, Sebastian Lackner
<sebastian at fds-team.de> wrote:
> On 19.01.2017 20:30, Julian Seward wrote:
>>
>> Hi Sebastian,
>>
>>> The Valgrind bugtracker also contains three patches I proposed back then. I
>>> was hoping that this would speed up the process of getting this fixed, but
>>> unfortunately it didn't help much. At many places Valgrind does not yet
>>> handle signal registers correctly and doesn't complain - except here, which
>>> is really unfortunate because even ignoring would be sufficient to make Wine
>>> happy.
>>
>> Sorry this fell through the cracks.  One underlying problem is that, some
>> time back in 2003, I learnt just enough about x86 segment stuff to hack up
>> what's currently in Valgrind, and then promptly forgot about it.  So I'm
>> not in much of a position to make an informed judgement now.
>>
>> That said .. I would be OK with a partial fix which improves Valgrind's
>> SS handling enough to make Wine work, so long as it doesn't create a
>> situation where other cases are silently handled incorrectly.  That is,
>> if the fix only moves forwards on the correctness scale, and doesn't
>> introduce any regressions.
>>
>> On rereading https://bugs.kde.org/show_bug.cgi?id=344139#c1 I see that you
>> have a candidate patch (http://ix.io/gKt, "Correctly handle the SS prefix
>> when explicitly specified.") which appears to have the abovementioned
>> properties.  Is that correct?
>>
>> J
>>
>
> As discussed on IRC, this direction probably makes most sense. In contrast to
> the other approaches, no special handling for the SS segment is required -
> nevertheless, we have to initialize some GDT entries to make this work.
>
> I have attached a new series which is hopefully less hacky:
>
> https://bugs.kde.org/show_bug.cgi?id=344139#c3 (*)
> https://bugs.kde.org/show_bug.cgi?id=344139#c4
>
> (*) On some systems the segment for DS and SS is the same, but initializing
> twice shouldn't hurt.
>
> For me it fixes the Wine tests (@Austin: Could you confirm?).
> Please let me know if you have any other suggestions for improvement (either
> here or on the bugtracker). Thanks!
>
> Best regards,
> Sebastian
>

With those two patches on top of r16203, I can run
dlls/advapi32/tests/service.c again without the trap 0 occurring

My wine/valgrind branch has one other patch, for
https://bugs.winehq.org/show_bug.cgi?id=39097. So I also tried
reapplying 4a1629c4117fda9eca63b6f56ea45771dc9734ac, and rerunning
dlls/comdlg32/tests/filedlg.c with valgrind, but it still hangs.

So the patches are good for me, but there's still at least one wine
and valgrind regression that needs to be investigated.

-- 
-Austin
GPG: 14FB D7EA A041 937B