title: Debugging techniques without debugging tools
body: <p>I find myself in the difficult situation of having to debug a Qt application without almost any debugging tool: the application seems to start using more and more CPU as it is running the same action again and again; after many hours CPU is completely saturated.</p>
  
  <p>The application runs on a ARM Linux embedded device where gdb seems not to work, maybe hard-to-discover problems with the provided toolchain. strace seems only to report timer activities (this is an OpenGL application so this is expected). ltrace is not available and compiling it resulted in a difficult task, maybe useless. I didn't write the application but the source code is available.</p>
  
  <p>Is there anything else I can do to discover what the application is busy doing when consuming that much resources? Any way I have to trace all the method calls the application does? Is there any other technique I can use to try to guess the problem or where to focus my attention?</p>
  
  <p>EDIT: This is one of the problems with gdb: <a href="https://stackoverflow.com/questions/8437526/only-question-marks-in-backtrace-reported-by-gdb-on-arm">Only question marks in backtrace reported by gdb on ARM</a>. Even writing a ten lines application simulating a segfault results in this.</p>