Bug#537572: gnome-settings-daemon can't connect to D-Bus and eats CPU on ia64 due to -Wl, -z-defs

[Émeric Maschino]

Le 14 novembre 2011 23:51, Jonathan Nieder <jrnieder at gmail.com> a écrit :
>> So, to summarize, only libgconf.so and libsmartcard.so didn't need to
>> be replaced by recompiled versions without -z defs flag. I don't know
>> if it'll help further, but they can even be removed from
>> /usr/lib/gnome-settings-daemon-3.0 and both GDM3 and GNOME3 session
>> still run flawlessly.
>
> Thanks, this is interesting.
>
> Now for some stupid questions:
>
>  - does linking with gold instead (i.e., installing binutils-gold)
>   change the outcome?

Sorry for the late reply. Unfortunately, Gold isn't available on ia64,
neither in Wheezy, nor Sid. And I can't make it compile successfully
:-(

>  - does using -Wl,--no-undefined in place of -Wl,-z,defs change
>   anything?

No. But since -z defs and --no-undefined are the same (from the
manpage), that's a good thing ;-)

>   Presumably -Wl,--no-undefined -Wl,--error-unresolved-symbols errors out --- what is the message when it does?

All the plugins complain about missing reference to
gnome_settings_plugin_get_type.

And some have additional missing references (mainly X11-related):
- a11y-keyboard: Xkb{Set|Get}Controls, XkbFreeKeyboard, XSync,
XkbQueryExtension, XkbSelectEvents;
- automount: XkbGetState;
- background: XInternAtom, XGetWindowProperty, XFree;
- clipboard: XSync, XInternAtom, XGetWindowProperty, XFree,
XChangeProperty, XConvertSelection, XSendEvent, XGetWindowAttributes,
XSelectInput, X{Set|Get}SelectionOwner, XCreateSimpleWindow,
XDestroyWindow, XExtendedMaxRequestSize, XMaxRequestSize, XIfEvent;
- keyboard: XkbFreeKeyboard, Xkb{Query|Use}Extension, XInternAtom,
XFree, XGetSelectionOwner, XAutoRepeat{On|Off}, XkbSetAutoRepeatRate,
XChangeKeyboardControl, XkbKeysymToModifiers, XkbSelectEventDetails,
XGetAtomName;
- mouse: floor, floorf, ceil, ceilf;
- print-notifications: notify_notification_new,
notify_notification_set_hint, notify_notification_show;
- xsettings: XInternAtom, XChangeProperty, XSendEvent, XSelectInput,
X{Set|Get}SelectionOwner, XCreateSimpleWindow, XDestroyWindow,
XIfEvent, X{Open|Close}Display, XResourceManagerString.

It's noteworthy than debian/rules top build script passes by default
--warn-unresolved-symbols to the linker, so the above missing
references are obviously hidden. I don't know if these missing
references are thus expected in the present context or if it's
expected that --warn-unresolved-symbols is passed to the linker rather
than --error-unresolved-symbols (default behavior from the manpage).

>  - what does using "-z defs" buy us when the error is demoted to a
>   warning by a later command-line option, anyway?  Though I still
>   don't understand what is causing this code path to break.

Sorry Jonathan, my limited English doesn't allow me to understand this
last section. What do you mean by "buy us"?

     Émeric