Comment 2 for bug 1538471

StacktraceTop:
 __libc_message (do_abort=do_abort@entry=1, fmt=fmt@entry=0x7fd789926128 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
 malloc_printerr (ptr=<optimized out>, str=0x7fd7899261a0 "free(): invalid next size (fast)", action=1) at malloc.c:4965
 _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3834
 __GI___libc_free (mem=<optimized out>) at malloc.c:2950
 _pygi_closure_handle () from /tmp/apport_sandbox_zFmgT3/usr/lib/python3/dist-packages/gi/_gi.cpython-35m-x86_64-linux-gnu.so