[fedora-arm] Broken sha512sum in coreutils / forcing alignment fixup and logging in initscripts

[omalleys at msu.edu]

Quoting Gordan Bobic <gordan at bobich.net>:

> On 01/09/2011 12:29 PM, Andy Green wrote:
>> On 01/09/11 12:09, Somebody in the thread at some point said:
>>
>>>> Sounds right. The user is going to google why his log is filling with
>>>> these warnings if he cares and the problem is bad, and this covers his
>>>> code as well as distro code (with the small window where the alignment
>>>> policy is still 0 from running init through actually setting the
>>>> alignment policy to fix+log if he doesn't know about the kernel
>>>> parameter).
>>>>
>>>> If he doesn't use Fedora initscripts, then he's at the mercy of the
>>>> kernel default alignment policy of "mangle data silently" but that's not
>>>> a Fedora problem.
>>>
>>> In can, however, see one good argument for warn+signal, and that is that
>>> abrt already picks up crashes for reporting so no change would be
>>> required there. Also a core dump would be useful to pin down the errors
>>> that aren't trivial to reproduce.
>>
>> Signal is pretty violent if, for example, once in a blue moon even init
>> or sshd can blow an alignment fault for some reason. It'd be very
>> interesting to find it in the logs but less interesting to find your
>> embedded Fedora device at the bottom of the ocean can't be logged into
>> any more for no real reason.
>
> I understand your point, but we're talking about defaults here, not
> specialist defices that were deployed by people knowledgeable of what
> they are doing. Fedora is a development/testing distribution, no a
> production/stable/enterprise one. Whould there ever be a release of RHEL
> for ARM, then that should perhaps have alignment=3 as default, and
> perhaps Fedora should have alignment=5 as default.

What you are talking about is a Segfault release. like make rawhide,  
alpha, beta, releases default to segfaults or at least proficiency log  
and report accurately enough to be able to find the errors to be fixed.

Then for the actual release change the default so they get fixed up.
We don't want to alienate people from the project and have it called  
buggy because it keeps crashing.

Does Neon, vFPU or any other simd besides sse < 2, actually do  
alignment fixups?
Can tree-autovec handle unaligned data?

Is there a way on intel arch to segfault or better detect the  
alignment errors? IE it fixes them on the fly but is there a way to  
turn that off or log it.. I mean can we push some of this burdon  
upstream and have it logged or fixed on hardware that is just more  
users of the project? And usually they are the package maintainers and  
on the actual project dev list and it makes it easier for them to  
report the bugs.

The logistics of fixing all of them even for large projects is going  
to take a long time unless someone has a killer compiler that can do  
like a direct download from git, compile it, find the errors, fix the  
errors and submit the patches back that make sense.  :P