compiz crashed with SIGSEGV in gdk_pixbuf_get_width()

StacktraceTop:
 gdk_pixbuf_get_width (pixbuf=<optimized out>) at gdk-pixbuf.c:581
 unity::hud::HudIconTextureSource::ColorForIcon (this=0x3fce850, pixbuf=0xa7730a7730a7730) at /build/buildd/unity-5.4.0/plugins/unityshell/src/HudIconTextureSource.cpp:47
 operator() (this=0x26b9800, texture=<optimized out>) at /build/buildd/unity-5.4.0/plugins/unityshell/src/HudIcon.cpp:60
 emit (_A_a1=@0x7fff454ad308, impl=0x327f680) at /usr/include/sigc++-2.0/sigc++/signal.h:1010
 emit (_A_a1=@0x7fff454ad308, this=<optimized out>) at /usr/include/sigc++-2.0/sigc++/signal.h:2781

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

reproduced by pressing CTRL+ALT to exit a VM that captured the cursor

Setting to critical it occurs pretty frequently when I press <ALT>

Gord told he will look into it.

This bug was fixed in the package unity - 5.6.0-0ubuntu1

---------------
unity (5.6.0-0ubuntu1) precise; urgency=low

  * New upstream release.
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