Unity FTBFS in Bionic

[Jeremy Bícha]

Unity fails to build from source in bionic.

On Monday, I was able to build Unity fine in my test PPA against gnome-desktop3 3.27.90.

https://launchpad.net/~jbicha/+archive/ubuntu/tempgnomedesktop/+packages

By Thursday, Unity no longer builds from source.
https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3156/+packages

So what's changed this week?
Well, there's a new mesa and a new glib2.0.

[Doug McMahon (mc3man)]

Local build here breaks on the new glib (tests only

[Khurshid Alam (khurshid-alam)]

Yes, it compiles with gnome-desktop3 3.27.90 but not with glib2.0 2.55.2-1ubuntu1 from bionic proposed.

[Khurshid Alam (khurshid-alam)]

@Jeremy

I tried Marco's branch. It is compiling for me with glib2.0 2.55.2-1ubuntu1.

https://code.launchpad.net/~3v1n0/unity/track-more-objects

[Jeremy Bícha (jbicha)]

Khurshid, I just rebuilt Marco's branch and it FTBFS, but at a different spot I believe.

See the PPA linked to from https://bileto.ubuntu.com/#/ticket/3138

[Khurshid Alam (khurshid-alam)]

From log:

CMake Error at plugins/unityshell/CMakeLists.txt:1 (find_package):
  By not providing "FindCompiz.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Compiz", but
  CMake did not find one.

  Could not find a package configuration file provided by "Compiz" with any
  of the following names:

    CompizConfig.cmake
    compiz-config.cmake

  Add the installation prefix of "Compiz" to CMAKE_PREFIX_PATH or set
  "Compiz_DIR" to a directory containing one of the above files. If "Compiz"
  provides a separate development package or SDK, be sure it has been
  installed.

[Marco Trevisan (Treviño) (3v1n0)]

To fix that issue you only need to recompile compiz too. And that's enough.

However, then the tests fail because of a crash inside libglvnd at exit:

#0 0x00007ffff3e0c11b in malloc_consolidate (av=av@entry=0x7ffff415dc20 <main_arena>) at malloc.c:4492
#1 0x00007ffff3e0de08 in _int_free (av=0x7ffff415dc20 <main_arena>, p=<optimized out>, have_lock=0) at malloc.c:4398
#2 0x00007ffff3e1244e in __GI___libc_free (mem=<optimized out>) at malloc.c:3145
#3 0x00007fffed5102dd in __glDispatchDestroyTable (dispatch=0x5555558d63c0) at GLdispatch.c:321
#4 0x00007fffed5df10f in CleanupVendorNameEntry (unused=0x0, pEntry=0x555555944210) at libglxmapping.c:311
#5 0x00007fffed5e8866 in __glXMappingTeardown (doReset=0) at libglxmapping.c:1061
#6 0x00007fffed5dec80 in __glXFini () at libglx.c:2099
#7 0x00007ffff7de621a in _dl_fini () at dl-fini.c:235
#8 0x00007ffff3dbeec0 in __run_exit_handlers (status=0, listp=0x7ffff415d6f8 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true, run_dtors=run_dtors@entry=true) at exit.c:83
#9 0x00007ffff3dbef1a in __GI_exit (status=<optimized out>) at exit.c:105
#10 0x00007ffff3da41c8 in __libc_start_main (main=
    0x5555556b9d45 <main(int, char**)>, argc=1, argv=0x7fffffffd128, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffd118) at ../csu/libc-start.c:342
#11 0x000055555568908a in _start ()
(gdb) f 3
#3 0x00007fffed5102dd in __glDispatchDestroyTable (dispatch=0x5555558d63c0) at GLdispatch.c:321
321 free(dispatch->table);
(gdb)

In fact when the nux windowthread is closed, and its graphic display is free'd we do a call to glXDestroyContext which leads to this crash because for some reason the dispatch->table is already free'd by something else (the driver?).

Getting rid of that line fixes the issue, but indeed isn't correct.

There's a comment on __glDispatchDestroyTable saying
    /*
     * XXX: Technically, dispatch->currentThreads should be 0 if we're calling
     * into this function, but buggy apps may unload libGLX without losing
     * current, in which case this won't be true when the dispatch table
     * is destroyed.
     */

Not sure if this is the case though, as it's quite cryptic to me.

[Marco Trevisan (Treviño) (3v1n0)]

Ok, actually it's something else... Bug this was caused by memory corruption as I was guessing.

See https://code.launchpad.net/~3v1n0/compiz/static-compregion-memory-curruption-fix/+merge/338342 and bug #1750619

[Jeremy Bícha (jbicha)]

https://launchpad.net/ubuntu/+source/unity/7.5.0+18.04.20180221.1-0ubuntu1

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity - 7.5.0+18.04.20180221.1-0ubuntu1

---------------
unity (7.5.0+18.04.20180221.1-0ubuntu1) bionic; urgency=medium

  * Unity use track_obj to safely connect to UScreen and Settings
    signals (LP: #1748330) (LP: #1748330)
  * CairoBaseWindow: don't try to compute the blur of an invalid texture
    (LP: #1290056)
  * Unity: use new definition of infinite CompRegion's (LP: #1749957)

 -- Marco Trevisan (Treviño) <[e-mail]> Wed, 21 Feb 2018 15:27:45 +0000