QT Creator Debugging with Breakpoints

Not sure if it is appropriate to ask QT related questions here. But I do have issues with Qt Creator Debugging. Debugging runs fine without breakpoints. If breakpoints are added, an error message (attached) pops up as soon as the program runs into a breakpoint. After clicking “OK” button of the message window, “Application Output” of QT Creator shows this message: “Child terminated with signal = 0x4 (SIGILL) Debugging has finished” and the program crashes. This does not happen when debugging with old 3.14.52 kernel running in the target device. The new 4.1.39 kernel was rebuilt from source code.
Any ideas of why this is happening with new kernel?


This sounds rather strange.
We know of an issue that prevents debugging at all. I.e. it does not start the application, with or without breakpoints.

What do you mean by ‘This does not happen when debugging with old 3.14.52 kernel’?
Do you only swap the uImage and the kernel modules? And not change everything, kernel and rootfs?

On what machine do you see the the popup for which you added a screenshot, and what program crashes?

Is there any output in the ‘Application Output’ and ‘Debugger Console’ pane?

What can you see in the debugger log output. (Window->Views->Debugger Log)


By saying ‘This does not happen when debugging with old 3.14.52 kernel’, I meant that debugger works fine with breakpoints enabled and target running 3.14.52 linux kernel. The image of that target was built with Toradex BSP 2.6.1. Rootfs was built with Yocto. The screenshot was taken on debugging host (ubuntu). It is the application program running in target and in debug mode that crashed.
Below is what’s in the “Application Output” before a breakpoint is hit:

Debugging starts Listening on port
10001 Remote debugging from host Process /home/root/hello created; pid = 620

When a breakpoint is hit, an error window pops up as attached screenshot. No output messages in “Application Output”. Click on “OK” button of the popup and “Continue” button of the debugger, the following messages appear in the “Application Output”:

Child terminated with signal = 0x4
(SIGILL) Debugging has finished

Here is debug log with 2 separated sections.


You seem to use a boot2qt setup which I’m not familiar with.

What is the version of the gdbserver on the target?

gdbserver --version

Does debugging work if you tell qtcreator to ignore SIGILL? e.g. adding the following in Options/Debugger, GDB tab, ‘Additional Startup Commands’?

handle 4 nostop noprint ignore

Is the application that you are debugging really a simple Qt style helloworld?