While editing main menu, xfce4-panel crashed with SIGSEGV in fast_validate()

[Alistair Buxton]

To reproduce:

1. Open the main menu properties.
2. Click "Edit" to open the menu editor.
3. Disable some launchers: mail reader, system settings, log out and/or launcher directories such as Accessories.
4. Attempt to reenable them - this does not work.
5. Disable a different launcher - notice that any launcher you tried to previously reenable (possibly an odd number of times) is now enabled.
6. Click on the main menu on the panel. The whole panel crashes.

Your panel is now totally broken. No amount of changes in the main menu editor will fix it. The only way to recover is to rm ~/.local/share/applications/*, then open the menu editor and click "restore system defaults".

Alacarte spits out this error when trying to reenable the disabled launcher items:

Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 343, in on_item_tree_show_toggled
    self.editor.setVisible(item, True)
  File "/usr/share/alacarte/Alacarte/MenuEditor.py", line 182, in setVisible
    self.writeItem(item, NoDisplay=False)
  File "/usr/share/alacarte/Alacarte/MenuEditor.py", line 408, in writeItem
    f.write(contents)
  File "/usr/lib/python2.7/codecs.py", line 691, in write
    return self.writer.write(data)
  File "/usr/lib/python2.7/codecs.py", line 351, in write
    data, consumed = self.encode(object, self.errors)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xd9 in position 262: ordinal not in range(128)

A quicker way to reproduce the xfce crashes:

"truncate --size 0 ~/.local/share/desktop-directories/xfce-accessories.directory"

This causes xfdesktop to instantly segfault, and xfce4-panel to segfault the next time you open the main menu.

ProblemType: Crash
DistroRelease: Ubuntu 13.10
Package: xfce4-panel 4.10.1-1ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-4.9-generic 3.11.0-rc7
Uname: Linux 3.11.0-4-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.12.1-0ubuntu2
Architecture: amd64
Date: Wed Aug 28 15:29:27 2013
ExecutablePath: /usr/bin/xfce4-panel
InstallationDate: Installed on 2013-08-27 (0 days ago)
InstallationMedia: Xubuntu 13.10 "Saucy Salamander" - Alpha amd64 (20130827)
MarkForUpload: True
ProcCmdline: xfce4-panel --display :0.0 --sm-client-id 2d7a344e9-88a4-4aeb-bbde-215467583950
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7fecdca51260 <g_utf8_validate+464>: movzbl (%rdi),%eax
 PC (0x7fecdca51260) ok
 source "(%rdi)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: xfce4-panel
StacktraceTop:
 g_utf8_validate () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 garcon_menu_directory_set_name () from /usr/lib/x86_64-linux-gnu/libgarcon-1.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 g_object_new_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 g_object_new () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
Title: xfce4-panel crashed with SIGSEGV in g_utf8_validate()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Alistair Buxton (a-j-buxton)]

This also puts xfdesktop into a permanent crash loop, but clearing out ~/.local/share/applications doesn't fix it.

[Apport retracing service (apport)]

StacktraceTop:
 fast_validate (str=<optimized out>) at /build/buildd/glib2.0-2.37.6/./glib/gutf8.c:1453
 g_utf8_validate (str=str@entry=0x0, max_len=max_len@entry=-1, end=end@entry=0x0) at /build/buildd/glib2.0-2.37.6/./glib/gutf8.c:1621
 garcon_menu_directory_set_name (directory=0x7fece0d7fba0, name=0x0) at garcon-menu-directory.c:441
 object_set_property (nqueue=0x7fece0e235b0, value=0x7fff2ac58ef0, pspec=0x7fece0e52ba0, object=0x7fece0d7fba0) at /build/buildd/glib2.0-2.37.6/./gobject/gobject.c:1366
 g_object_new_internal (class=class@entry=0x7fece0e61e10, params=params@entry=0x7fff2ac58fd0, n_params=<optimized out>) at /build/buildd/glib2.0-2.37.6/./gobject/gobject.c:1797

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel Letzeisen (dtl131)]

I could only reproduce the alacarte (mis)behavior.

I don't have a ~/.local/share/desktop-directories directory to test that command.

[Alistair Buxton (a-j-buxton)]

It should be enough to create the directory, I think. That's what alacarte is doing - making the directory, making the file, then crashing when it tries to write a non-ascii character, so the files end up empty which xfce can't handle.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Alistair Buxton (a-j-buxton)]

Hello duplicate bug reporters. This bug has been fixed upstream and the fix is in trusty.

[Thaddaeus Tintenfisch (thad-fisch-deactivatedaccount)]

Fixed in Ubuntu 14.04 (Trusty Tahr).