[Qt-creator] Debugger hangs on breakpoint (near QSGRenderThread)

[André Pönitz]

On Tue, Oct 29, 2013 at 09:38:12PM +0000, Mateusz Loskot wrote:
> Hi,
> 
> I'm using Qt Creator 3.0.81 (Qt 5.2.0 64-bit) on Linux,

[As a side note: 'master' is usually unattended between about
a week before beta releases and the release candidate, it's
really not recommended to use, even for 'bleeding edge' cases
during that time]

> 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:
> http://imageshack.com/a/img577/6858/ccqe.png
> http://imageshack.com/a/img5/5714/kdn7.png
> http://imageshack.com/a/img850/5031/9wvl.png

This pretty much looks like an unclean build.

> 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?

I'd 'git clean -dxf ; qmake ; make' (for a checkout from 3.0 branch)
and check whether the problem persists. If it does, file a bug and
attach the debugger log (contents of the right pane of Windows->
Views->Debugger)

Andre'