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Re: Ruby testsuite failures because of pointer mangling on 32-bit ARM?


On 10 December 2013 10:30, Will Newton <will.newton@linaro.org> wrote:
> On 10 December 2013 01:49, Carlos O'Donell <carlos@redhat.com> wrote:
>
> Hi Carlos,
>
>> I've had one report that the pointer mangling support on 32-bit ARM
>> that was added in October might be causing the Ruby [1] testsuite
>> to fail.
>>
>> Could you try running the ruby testsuite yourself using the new
>> 32-bit glibc runtime to see if you can reproduce the problem
>> yourself?
>
> Sure, I'll take a look.

So the question I have now is how does this work on other architectures? ;-)

Ruby uses jmpbuf as a context object for doing threading but also at
gc.c:1845 it seems to be using a jmpbuf to mark the root set for GC
which if we are encrypting FP (which is usually a general purpose
register on ARM) then that may fail and the GC could end up collecting
live data.

I haven't managed to run the Ruby testsuite as it just seems to have
loads of failures with or without the pointer encryption support. I
guess I am running it wrong somehow.

I'll post a patch. If  you could test it with Ruby that would be much
appreciated.

Thanks,

-- 
Will Newton
Toolchain Working Group, Linaro


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