mate-panel crashed with SIGSEGV in free()

[LAZA]

crashed after login, nothing done (VM)

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: mate-panel 1.12.2-1
ProcVersionSignature: Ubuntu 4.4.0-15.31-generic 4.4.6
Uname: Linux 4.4.0-15-generic x86_64
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: MATE
Date: Sun Apr 10 10:51:12 2016
ExecutablePath: /usr/bin/mate-panel
InstallationDate: Installed on 2016-02-26 (43 days ago)
InstallationMedia: Ubuntu-MATE 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160224)
ProcCmdline: mate-panel
ProcEnviron:
 LANGUAGE=de_DE
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f5022decbc2 <free+34>: mov -0x8(%rdi),%rax
 PC (0x7f5022decbc2) ok
 source "-0x8(%rdi)" (0x00000005) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: mate-panel
StacktraceTop:
 free () from /lib/x86_64-linux-gnu/libc.so.6
 g_hash_table_unref () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_slist_foreach () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
 g_object_unref () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
Title: mate-panel crashed with SIGSEGV in free()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
XsessionErrors:
 mate-session[1284]: WARNING: Unable to find provider '' of required component 'dock'
 (tilda:1572): Gtk-WARNING **: Failed to fetch network locations: Zeitüberschreitung wurde erreicht
 (mate-panel:1533): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
 (nm-applet:1570): Gdk-CRITICAL **: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed

[Apport retracing service (apport)]

StacktraceTop:
 free () from /tmp/apport_sandbox_MjakNe/lib/x86_64-linux-gnu/libc.so.6
 ?? ()
 ?? ()
 ?? ()
 ?? ()