Re: Please revert 709f744 (x86: bitops asm constraint fixes)

From: Jan Beulich
Date: Wed May 07 2008 - 03:50:18 EST


>>> Thomas Gleixner <tglx@xxxxxxxxxxxxx> 07.05.08 09:43 >>>
>On Wed, 7 May 2008, Jan Beulich wrote:
>> >>> Ingo Molnar <mingo@xxxxxxx> 06.05.08 14:01 >>>
>> >Jan, any ideas what's wrong with your commit?
>>
>> No, I have no idea at all (apart from considering mis-compilation as you
>> did. The best path I could suggest is to try and nail this down to one
>> (or more, if that happens to be the case) function(s) having been
>> changed - this is mostly because part of the changes are really
>> tightening things (which therefore I would think ought to be kept),
>> while the change to __test_and_change_bit() really weakens things
>> (which I nevertheless continue to think is correct and consistent with
>> other functions, but which then would be the primary suspect). Of
>> course, since no-one else has seen this so far, this would need to be
>> done by Simon.
>> Once down to a single (hopefully) function, it might be possible to just
>> statically compare the two vmlinux-es to perhaps spot whether this
>> indeed is mis-compilation.
>
>Jan,
>
>can you please provide a step by step conversion of those constraints
>on top of the revert. I'm a bit wary about this whole business as such
>constraint problems might hit us elsewhere as well.

I certainly can, but I can't promise when I'd get to do this (may be days
to weeks - sorry for that).

Jan

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