_ [debian] trace trap (core dumped) firefox

(firefox:XXXXX): Gdk-ERROR **: The program 'firefox' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial XXXXX error_code 143 request_code 139 (RENDER) minor_code 7)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the GDK_SYNCHRONIZE environment
   variable to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

[1]  + trace trap (core dumped)  firefox

みたいにクラッシュするようになったので、指示の通り GDK_SYNCHRONIZE=1 して起動するようにして様子見。