Bug#790825: vlc crashes when laptop is undocked

[Sebastian Ramacher]

Hi Michael

On 2015-07-02 14:42:25, Michael Biebl wrote:
> Am 02.07.2015 um 14:04 schrieb Sebastian Ramacher:
> > Control: tags -1 + moreinfo
> > 
> > Hi
> > 
> > On 2015-07-02 04:11:03, Michael Biebl wrote:
> >> when I start vlc and then undock my laptop, vlc crashes. This is from
> >> dmesg:
> >>
> >> [  371.966646] usb 3-1.1.3.2: USB disconnect, device number 9
> >> [  371.970358] vlc[3908]: segfault at 28 ip 00007fef7cb2a4c7 sp
> >> 00007fef7c1ef210 error 4 in libQt5Widgets.so.5.4.2[7fef7c991000+66e000]
> >> [  372.402515] thinkpad_acpi: undocked from hotplug port replicator
> > 
> > Could you please install vlc-dbg and qtbase5-dbg and produce a backtrace?
> 
> Backtrace is attached. I've also attached the xrand output before and
> after the undock.
> This issue is 100% reproducible here, so I can run further diagnostics,
> test patches etc if you want me to.

Thanks. I think this is a Qt 5 issue. I am able to produce a similar backtrace
with the following example program [1]:

$ cat main.cpp
#include <QApplication>
#include <QGraphicsScene>
#include <QGraphicsView>

int main(int argc, char** argv)
{
  QApplication app(argc, argv);

  QGraphicsScene scene;
  scene.setSceneRect(-100.0, -100.0, 200.0, 200.0);
  scene.addText("Hello, world!");

  QGraphicsView view(&scene);
  view.setRenderHints(QPainter::Antialiasing);
  view.show();

  return app.exec();
}

$ cat CMakeLists.txt
cmake_minimum_required(VERSION 2.8.11)
project(testproject)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)

find_package(Qt5Widgets)

add_executable(helloworld main.cpp)
target_link_libraries(helloworld Qt5::Widgets)


Can you confirm that this example also crashes for you?

Cheers

[1] I don't have docking station, but waking up from suspend triggers the same
code path. Interestingly enough it only happens if I close the lid and not if
the manually trigger a suspend.
-- 
Sebastian Ramacher

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