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Re: Ruby testsuite failures because of pointer mangling on 32-bit ARM?
- From: Will Newton <will dot newton at linaro dot org>
- To: "Carlos O'Donell" <carlos at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 10 Dec 2013 17:25:43 +0000
- Subject: Re: Ruby testsuite failures because of pointer mangling on 32-bit ARM?
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- References: <52A6732E dot 4030905 at redhat dot com> <CANu=DmgWNhyxq9vE37bvvD=PrDrfi0Y+eAMv0i2KZPxaEnEOxw at mail dot gmail dot com>
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