Debugger hangs on breakpoint (near QSGRenderThread)
Originally, I posted this to the qt-creator mailing list: "Debugger hangs on breakpoint (near QSGRenderThread)":http://lists.qt-project.org/pipermail/qt-creator/2013-October/002839.html
I haven't received any responses, so I decided to re-post it here trying to reach a wider community.
I'm using Qt Creator 3.0.81 (Qt 5.2.0 64-bit) on Linux, built on October 26 from the source code pulled from the Git repository. It's debug/development build and I'm using two separate copies of the build: one to develop, the other to lauch and debug a plugin.
While debugging some plugins and I've noticed that the debugging session freezes once the execution reaches some of breakpoints. It happens fairly often, but I haven't noticed the exact pattern of what kind of breakpoints actually make the debugger freeze.
For example, I placed breakpoint in the CMakeProjectManager plugin's CMakeBuildConfigurationFcatory::availaleBuilds() method, then:
- the execution stops at it, then 1-5 seconds later
- the stacktrace refreshes view and displays completely unrelated,
- the step over/in/out buttons get disabled,
- the debugger is not responding on stepping,
- the only buttons that are active are pause and stop.
Here are three screenshots to show what's going on during the sequence above:
- Qt Creator 1: breakpoint vs stacktrace in different thread
!http://imageshack.com/a/img577/6858/ccqe.png(Qt Creator 1: breakpoint vs stacktrace in different thread)!
- Qt Creator 2: added breakpoint vs stacktrace & stop requested
!http://imageshack.com/a/img5/5714/kdn7.png(Qt Creator 2: added breakpoint vs stacktrace & stop requested)!
- Qt Creator 3: added breakpoint vs stacktrace & Attempting to interrupt
!http://imageshack.com/a/img850/5031/9wvl.png(Qt Creator 3: added breakpoint vs stacktrace & Attempting to interrupt)!
Interestingly, every time it happens, the view title bar displays QSGRenderThread and "Running" next to it.
If I hit the blue pause button, it changes to "Stop requested" and eventually it shows "Attempting to interrupt" which hangs forever.
The only thing I can do is to abort debugging and restart it.
I noticed similar issue while debugging other plugins like the GenericProjectManager and others.
I wonder, is this something known?
Do I need to tweak the Qt Creator/GDB debugger settings in some way?
Does it look like a bug and shall I report?
Mateusz Loskot, http://mateusz.loskot.net
FYI, this problem has been solved with "André Pönitz' diagnosis":http://lists.qt-project.org/pipermail/qt-creator/2013-October/002844.html of unclean build.
Quick tests prove that after switching to branch 3.0 and clean rebuild all works well, but I'll wait a bit and continue testing before I mark this topic as solved.