"QObject::startTimer: timers cannot be started from another thread" without timers && CPU consumption

I created a multithreaded application in Qt (4.7.2). Only the main thread has an event loop.

The issue is that sometimes I get the following warning in the console:

QObject::startTimer: timers cannot be started from another thread

After this happens, the app consumes 100% of CPU (I have a single core CPU). It seems, that the main thread consumes all of the CPU's resources. The program does not freeze, and everything still works.

When I stop the program in the debugger, I do not see my code in the call stack.

The problem is that I'm not using (explicitly, anyway) timers at all.

What could it be connected with? I know, that question is very common, but I can't even understand, what piece of code to show.