uptime / w coredumping on RELENG11 (i386 only)

[Dewayne Geraghty]

On 17/05/2018 7:17 AM, Dimitry Andric wrote:
> On 16 May 2018, at 15:54, Mike Tancsa <mike at sentex.net> wrote:
>> On 5/15/2018 2:31 PM, Dimitry Andric wrote:
>>> On 15 May 2018, at 20:22, Mike Tancsa <mike at sentex.net> wrote:
>>>>> Anyone else see this ?
>>> See <https://bugs.freebsd.org/227552>.  There is a fix coming up.
>> I tried the patch and did a full rebuild and it indeed fixed the problem
>> for me.  Is the bug potentially more wide spread that just libxo ? Also
>> does it possibly affect amd64, just in a non obvious way ?
> Yes to both, at least theoretically.  The problem is actually in
> elftoolchain's strip command, which can mess up the TLS section in an
> executable or shared library.  When the dynamic linker loads such a bad
> file, it will setup incorrect TLS data, which can lead to crashes.
>
> In case of libxo.so.0, this appears to have been caused by clang 6
> giving a slightly different ELF layout than clang 5.  During buildworld,
> libxo.so.0 is built with debugging information, which is later copied
> to a libxo.so.0.debug file, while it is removed from the original
> libxo.so.0 file.
>
> Up to this point, everything is still fine with libxo.so.0, still, but
> during installworld, the file is stripped *again*, by install -s (this
> is something we should revisit because it seems no longer useful).  This
> second round of stripping messes up the TLS section.
>
> -Dimitry
>
Revisit? Perhaps, but it seems that its a regression against clang6 over
clang5.  Looking at
https://svnweb.freebsd.org/base?view=revision&revision=333600
its appears that the section flags are correctly applied now.  When
333600 enters 11.1Beta?, do you think the build/installation process
requires revision?

Its a little disappointing to hear that the stripping process breaks the
output, if applied >1.

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