script plugin, i386, Ubuntu and a crazy regression

[Ray Strode]

Hi,


On Thu, Jun 27, 2013 at 5:23 PM, Steve Langasek <
steve.langasek at canonical.com> wrote:

> Hi folks,
>
> In Ubuntu 13.04, which ships with plymouth 0.8.8 and by default uses a
> theme
> that uses the script plugin, we are seeing reports that text labels are not
> displayed on x86 (32-bit).

Only 32-bit ? interesting.


> I've tracked this regression down to a single commit upstream,
> 3f8bd998dcc6d592ffd5d3aefad06f0bbf28a725, which adds a single line of
> initialization code to the script plugin's math library:
>
>  srand ((int) ply_get_timestamp ());
>
> It is utterly bewildering that this line has a side effect of causing text
> to not be displayed.
>
> Worse, it's not the srand() call that triggers it... if I just call
> ply_get_timestamp() and discard the result, the problem is still
> reproducible.
>
So ply_get_timestamp() returns a double which is a 64-bit type.
Maybe a missing #include "ply-utils.h" or something like that is (somehow)
triggering the problem?
Still not clear why this problem would manifest that way, but usually
32-bit only problems are something like a missing include or similar.  Does
compiling with optimization disabled "fix" it? Hand waving, withouth really
knowing, i'll say it could be the compiler is making assumptions during the
optimization process that aren't holding true because of the missing
prototype and the impliciit return type.

Has anyone seen such such behavior on other distributions?  Anyone have any
> insight into what mysterious side effects of ply_get_timestamp() - but only
> when called as a library function - are breaking display of strings via
> pango?
>
Another thought is the label plugin is failing to load.  debug text should
show the dlerror() from the failure if that's happening.  Maybe adding an
explicit -lrt somewhere is needed?

--Ray

>
>
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