I have a project built against libqjson0 (Ubuntu 16.04), which has the -dev and -dbg packages also installed. When debugging, an error in this qjson library causes causes a segmentation fault that repeatedly and endlessly produces new SIGSEGV dialog windows that eventually completely hang my X server such that I have to kill the whole Xorg process and re-login to a new session.
I then used qmake command line tools to build the project and then debug it with gdb. gdb correctly stops on the line causing the seg fault specified by the debug symbols of the qjson library, however gdb is unable to locate the source file indicated. It appears the qjson debug symbols have a non-portable path for the qt base source files.
qtcreator should not go into an endless loop which causes system-wide problems in the event the debug symbols point to an incorrect source code path when a runtime error occurs.