server/core/buffer.cc
In the method 'GWBUF* gwbuf_clone(GWBUF* buf)'. The pointer 'rval->tail' should be updated if there are more than one GWBUF objects need to be cloned, but it is not.
The problem is, while the job of method 'gwbuf_clone' is done, the pointer 'rval->tail' does not point to the last GWBUF object in GWBUF object list, but 'rval' itself.

Maybe we should add a line 'rval->tail = clonebuf;' after the line 'clonebuf = clonebuf->next;'?