Multiple quick clicks on launcher icon with multiple windows completely crashes Unity

Eylem: I'm sure you'll get a longer answer, for the moment, a workaround (that allows you to carry on, and/or save your work) is:

  Ctrl-Alt-F1
  killall -9 compiz
  unity --replace
  Ctrl-Alt-F8 (and wait 10-15 seconds for unity to "catch up"... for some reason it takes a long time to enumerate the existing open windows)

The other bug is that sometimes 'gnome-screensaver' opens (invisibly) on top of everything a "killall gnome-screensaver" from Ctrl-Alt-F1 will nuke that.

Paul, thank you for this great tip! I knew something was borked but had no idea what process to kill and/or start.

I really hope a dev can pinpoint the problem and solve it. Please let me know if there is any log file or something that I should attach. Thanks!

This does sound serious. Could you please provide a stack trace by following the instructions provided at, https://wiki.ubuntu.com/Unity/FilingBugs#Getting%20a%20stack%20trace and then attach the unity.log file to this report?

Alex, thank you for your attention! I did as you told and I am now attaching the unity.log file. I really hope it helps!

Paul, your suggestion for a workaround does not work. I mean unity (or compiz) does not start, the command (unity --replace) terminates with segmentation fault and exits. So far I've been unable to recover from this crash. It's very serious and it doesn't take much to trigger it. I just had a crash when I had two Nautilus windows on two different workspaces and I clicked once on the Nautilus launcher icon: boom.

Hi,
I uploaded the unity.log file. Please let me know if you need anything else. Thanks!

Thanks for the log, I'm setting to triaged.

I can reproduce this issue but with I get 3 different type of bugs:
1. Unity / Compiz crash as described in the original report
2. Only unity-panel-service crashes
3. Nothing crashes but the icon in the launcher vanished and the app linked to this icon close suddenly (all the instances).

Note that in the third case, the icon disappear, the windows of the application disappear too but the application is still running. It's just that it becomes invisible and there's is no way to make it come back.

Jean-Baptiste, thank you for looking into this. I can confirm that I experienced both cases 1 and 3 as you put in comment #7.

I had case 1 with Evince, Libreoffice, Nautilus, and Gedit, and it seems like it doesn't matter what the application is.

I had case 3 with Evince, Libreoffice and Mathematica. Till your post I hadn't thought they were related. But both cases are triggered by clicks on the Launcher icons, and clicks don't have to be too many or too quick.

I can easily say that both cases become more probable as the Unity session uptime gets longer. I had reported another bug where long uptimes causes the Launcher not to hide or dodge. Might be related if there is some kind of degradation in Launcher (or Compiz?) as time goes (I'm not a developer, but I'm sure you can put this vague sentence into context).

I'm not sure what you mean by case 2. When it happens, window decorations are still there but the top panel and Launcher are gone? I don't think I had that one then...

I'm not sure if it's related by I've been experiencing this crash incredibly often after 3.6.6. Sure a lot of things were fixed but something got broken in the meantime. It's the same crash as above but it's being triggered by the simplest of things kind of spontaneously. Three times in the last hour! Once I clicked Alt-Shift-Up (Expo), once I was customizing Thunderbird toolbar, once I clicked Alt-Left in Nautilus.

Please take a look at this, I cannot be the only one...

Hi, we've fixed this with the latest unity (3.8.2), please re-open if it's still an issue, thanks!

This bug was fixed in the package unity - 3.8.4-0ubuntu1

---------------
unity (3.8.4-0ubuntu1) natty; urgency=low

  * New upstream release.
    - [fglrx] compiz crashed with SIGSEGV in nux::IOpenGLSurface::UnlockRect()
      (LP: #685682)
    - SIGSEGV in g_atomic_int_get (LP: #688803)
    - unity-panel-service crashed with SIGSEGV in bamf_factory_view_for_path()
      (LP: #717684)
    - New window tracking system breaks in the case where windows try to
      restack relative to destroyed windows that were never mapped
      (LP: #723014)
    - Numpad 'Enter' doesn't work on highlighted items in dash, places-files and
      places-apps (LP: #741615)
    - compiz crashed with SIGSEGV in free() (LP: #738864)
    - compiz crashed with SIGSEGV in g_closure_invoke() (LP: #741674)
    - compiz crashed with SIGSEGV in CompWindow::id() (LP: #742028)
    - Windows that reparent away from the root before they are mapped can
      cause other windows to become invisible (and compiz to crash)
      (LP: #743011)
    - compiz crashed with SIGABRT in raise() (LP: #743414)
    - compiz crashed with SIGSEGV in g_object_get_qdata() (LP: #742905)
    - compiz crashed with SIGSEGV in g_closure_invoke() (LP: #748033)
    - compiz crashed with SIGSEGV in CompScreen::dpy() (LP: #751372)
    - compiz crashed with SIGABRT in __kernel_vsyscall() (LP: #744867)
    - unity-window-decorator crashed with SIGSEGV in gdk_window_get_events()
      (LP: #725284)
    - Missing icons in app launcher (LP: #728393)
    - Multiple quick clicks on launcher icon with multiple windows completely
      crashes Unity (LP: #731790)
    - Add a test case for invisible windows regressions (LP: #736876)
    - Re-sync with xquerytree to avoid stacking order issues (LP: #740465)
    - Wrong window moves (LP: #741656)
    - compiz crashed with SIGSEGV in g_cclosure_marshal_VOID__VOID()
      (LP: #742280)
    - panel superposition (LP: #742859)
    - unity-window-decorator doesn't start on secondary X session
      (LP: #730495)
    - Unity Launcher stops autohiding and is not responsive (LP: #744325)
    - dash categories dropdown menu leaves "ghost" on desktop (LP: #746800)
    - new dialogs open close enough of the launcher to make hide (LP: #747302)
    - dnd from the application place to the launcher works only once
      (LP: #747316)
    - compiz crashed with SIGSEGV in CompWindow::id() while opening tcl/tk
      interface of R (LP: #747439)
    - minimize animates window fading to the top left corner (ubuntu symbol)
      (LP: #747765)
    - Spread - Clicking on a app icon to spread the windows must always show
      all the windows, regardless of whether or not some of the windows are
      minimised (LP: #750349)
    - Launcher - Show visual de-coupling of Launcher app icons (LP: #751196)
    - unity-window-decorator crashed with SIGSEGV in event_filter_func()
      (LP: #748317)
    - Pressing Super-W to switch windows also presents Dash (LP: #753453)
    - Don't create windows over the launcher (LP: #688816)
    - Unity Grid is broken for multi-monitor setups (LP: #709221)
    - F10 key does not move focus to indicators when on the desktop.
      (LP: #727548)
    - dynamic ...

Still present in, or regressed to, version 7.4.0

The way I reproduced it is slightly different from OP: Repeat high speed clicking on a program icon with multiple windows until crash occurs. Crash is not total and windows are still usable but the launcher status looks crippled.

Launching `unity &` in a terminal fixes it, and it comes up with a crash reporter saying that the crash report is corrupt and cannot be processed.