[fedora-arm] F13 glibc patches for ARM?

[Niels de Vos]

On 14 Aug 2011 13:45, "Gordan Bobic" <gordan at bobich.net> wrote:
>
> On 08/14/2011 07:55 AM, Niels de Vos wrote:
>>
>> On 14 Aug 2011 00:30, "Gordan Bobic" <gordan at bobich.net
>> <mailto:gordan at bobich.net>> wrote:
>>  >
>>  > On 08/13/2011 10:23 PM, Niels de Vos wrote:
>>  >>
>>  >> On Sat, Aug 06, 2011 at 10:24:03AM +0100, Andrew Haley wrote:
>>  >>>
>>  >>> On 08/05/2011 09:07 PM, Gordan Bobic wrote:
>>  >>>>
>>  >>>> Thanks for pointing out, it does look like the same bug. So what's
the
>>  >>>> fix/workaround?
>>  >>>>
>>  >>>> On 08/05/2011 08:59 PM, Niels de Vos wrote:
>>  >>>>>
>>  >>>>> On 5 Aug 2011 19:15, "Gordan Bobic"<gordan at bobich.net
>> <mailto:gordan at bobich.net>
>>  >>>>> <mailto:gordan at bobich.net <mailto:gordan at bobich.net>>>  wrote:
>>
>>  >>>>> >
>>  >>>>> >  How does one pick the correct "ports" part of glibc for the
>> correct core?
>>  >>>>> >
>>  >>>>> >  I tried to build the RHEL6 glibc with the F13 ports tar ball,
>> but the
>>  >>>>> >  build eventually fails:
>>  >>>>> >
>>  >>>>>
>>
/usr/lib/gcc/armv5tel-redhat-linux-gnueabi/4.4.5/libgcc_eh.a(unwind-arm.o):
>>  >>>>> >  In function `__gnu_Unwind_Backtrace':
>>  >>>>> >  (.text+0x8b8): undefined reference to `__stack_chk_guard'
>>  >>>>> >  collect2: ld returned 1 exit status
>>  >>>>>
>>  >>>>> Looks very much like the error in
>>  >>>>> https://bugzilla.redhat.com/show_bug.cgi?id=726495
>>  >>>
>>  >>>
>>  >>> What is it linking against?  __stack_chk_guard should be defined in
>>  >>> libc.a.
>>  >>
>>  >>
>>  >> Adding -W,l:$PATH_TO_JUST_COMPILED/libc.a seems to work. The linker
than
>>  >> finds __stach_chk_guard for the .so's that require -static-libgcc.
This
>>  >> hack is now attached to Bug 726495. A scratch build is also running,
in
>>  >> a local mock it was successful:
>>  >> - http://arm.koji.fedoraproject.org/koji/taskinfo?taskID=151594
>>  >>
>>  >> I'm really not sure how the linker is supposed to find libc.a (which
was
>>  >> compiled a little earlier during the building of the glibc package).
It
>>  >> works for other architectures, so there must be some trick
somewhere...
>>  >>
>>  >> (Note, this is all for F-14's glibc-2.13 on armv5tel.)
>>  >
>>  >
>>  >
>>  > Interesting, I'll look into that. I'm currently looking at this bug
>> in relation to the glibc build issues:
>>  > https://bugzilla.redhat.com/show_bug.cgi?id=708452
>>
>> The result of bug 708452 was the inclusion of a patch for
>> tzdata-update.c in upstream. That bz did not fix the __stack_chk_guard
>> compile issue. I would advise you to with the argument from Jakub and do
>> not break unwinding.
>
>
> What about the other ARM specific spec changes from the F13 version?
Things like:
>
> %ifarch %{arm}
> BuildFlags="$BuildFlags -fno-asynchronous-unwind-tables
-fno-stack-protector"
> %else
> BuildFlags="$BuildFlags -fasynchronous-unwind-tables"
> %endif

My assumption is that adding libc.a for -static-libgcc fixes the build
issues. __stack_chk_guard is (part of) the stack protector which is used for
the unwinding of backtraces/exceptions.

Hth,
Niels
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