Re: Urgent: x86-32 and GNU ld 2.22.52.0.1
From: H.J. Lu
Date: Fri May 18 2012 - 12:16:41 EST
On Fri, May 18, 2012 at 9:14 AM, H.J. Lu <hjl.tools@xxxxxxxxx> wrote:
> On Fri, May 18, 2012 at 8:56 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> I need an urgent opinion. It seems we have an epic mess on our hands.
>>
>> GNU ld 2.22.52.0.1 silently changed the semantics of section-relative
>> symbols that are part of otherwise empty sections, and silently changes
>> them to absolute. We rely on section-relative symbols staying
>> section-relative, and actually have several sections in the linker
>> script solely for this purpose.
>
> That is I talked to you a couple days ago:
>
> http://sourceware.org/bugzilla/show_bug.cgi?id=14052
>
>> The postprocessor for the x86-32 kernel, relocs.c, currently doesn't
>> enforce its audited absolute symbols list. As part of the
>> tip:x86/trampoline rework, however, I made it error out rather that
>> silently producing bad output.
>>
>> Ingo has found that with this particular version of GNU ld, the error
>> triggers. I want to emphasize that this merely catches an error which
>> the current version of the tool would have allowed to silently go by,
>> which would have (possibly) caused a failure if the kernel was
>> subsequently booted in anything but its default location.
>>
>> There are a few ways we can deal with this, but I think we need to do
>> one or the other:
>>
>> 1. We can blacklist this version of GNU ld.
>
> I think this is the best approach.
>
Please verify that binutils 2.22.52.0.2 is broken
and binutils 2.22.52.0.1 is OK.
--
H.J.
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