Regression caused by commit 7682323a3a798d6f15708f228f859a64cb869aa3

[Khem Raj]

On Fri, Jan 13, 2012 at 4:13 PM, Khem Raj <raj.khem at gmail.com> wrote:
> On Fri, Jan 13, 2012 at 3:45 PM, Khem Raj <raj.khem at gmail.com> wrote:
>> On Fri, Jan 13, 2012 at 1:37 AM, Carmelo AMOROSO <carmelo.amoroso at st.com> wrote:
>>>> and since I see the same issue on all architectures probably its not
>>>> elfinterp changes
>>>> too. Mostly it seems likely that it could be in the way the scopes are
>>>> being handled
>>>>
>>>
>>> we have reviewed several times this change before committing. Anyway we
>>> will review it again. We have not ever seen any failure in the lookup
>>> with all of our tests. The only change in the way the symbol scope is
>>> created is in where the ld.so is added.
>>> In the original code it was the last entry of the global scope, while
>>> with the new structure in place it was added as soon as found (as glibc
>>> actually does).... and I don't really think this could have some impact.
>>
>> I tried to reverse it as well but the problem remained.
>>
>>>
>>> We are trying to startup a X system on our platform. Is there any simple
>>> X app we can run to show the failure ?
>>>
>>> Is some .so failing to be dl-opened due to unresolved symbol ?
>>
>> this is potentially possible. I will try to debug it through
>
> This is the problem that happens with the new scoping and does not
> happen without it
>
> Error reading Pango modules file
>
> (matchbox-desktop:1058): Pango-CRITICAL **: No modules found:
> No builtin or dynamically loaded modules were found.
> PangoFc will not work correctly.
> This probably means there was an error in the creation of:
>  '/etc/pango/pango.modules'
> You should create this file by running:
>  pango-querymodules > '/etc/pango/pango.modules'
>
> (matchbox-desktop:1058): Pango-WARNING **: failed to choose a font,
> expect ugly output. engine-type='PangoRenderFc', script='latin'
>
> (matchbox-desktop:1058): Pango-WARNING **: failed to choose a font,
> expect ugly output. engine-type='PangoRenderFc', script='common'

here is the error

/usr/bin/pango-querymodules: can't resolve symbol
'_ZNSt14error_categoryD2Ev' in lib '/usr/lib/libstdc++.so.6'.

this does not happen without scope patch

pango-querymodules loads a shared library
/usr/lib/pango/1.6.0/modules/pango-basic-fc.so using dlopen and this
library had libstdc++.so.6 in its DT_NEEDED entries

I was trying to create a small testcase where I created a small binary
which would dlopen another .so which has libstdc++ in DT_NEEDED in its
header so not able to reproduce a small testcase but making some
progress