Error when trying to run FlightGear with three monitors

[Thiyagu]

while running flightgear3.0. application in 3 window display with 3 K5000 nvidia quadro graphics and 1 DELL precision T7610 PC(64 gb RAM) i am facing this error.

"Warning: deleting still referenced object 0x7f7fb8002220 of type 'PN3osg10ReferencedE' the final reference count was 4294967295 memory corruption possible"at ../src/Viewer/fg_os_osgviewer.cxx:202
202 *trigger_segfault = 0;
(gdb) bt
#0 0x00000000004c55ab in NotifyLogger::notify (this=0x172ba00,
severity=osg::WARN,
message=0x7fffcc004408 " the final reference count was 4294967294, memory corruption possible.\n") at ../src/Viewer/fg_os_osgviewer.cxx:202
#1 0x00007ffff7408528 in osg::NotifyStreamBuffer::sync() ()
from /usr/lib/libosg.so.80
#2 0x00007ffff2ef432e in std::ostream::flush() ()
from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3 0x00007ffff74358bd in osg::Referenced::~Referenced() ()
from /usr/lib/libosg.so.80
#4 0x00007ffff7408cea in osg::Object::~Object() () from /usr/lib/libosg.so.80
#5 0x00007ffff5a59cc1 in osgUtil::RenderStageCache::~RenderStageCache() ()
from /usr/lib/libosgUtil.so.80
#6 0x00007ffff5a59d2a in osgUtil::RenderStageCache::~RenderStageCache() ()
from /usr/lib/libosgUtil.so.80
#7 0x00007ffff7435b98 in osg::Referenced::signalObserversAndDelete(bool, bool) const () from /usr/lib/libosg.so.80
#8 0x00000000004a8667 in osg::Referenced::unref (this=0x7fffc4004230)
at /usr/local/include/osg/Referenced:198
#9 0x0000000000615589 in osg::ref_ptr<osg::Object>::operator= (
this=0x1cd8140, ptr=0x7fffcc0041b0) at /usr/local/include/osg/ref_ptr:58
#10 0x00007ffff5a46bcc in osg::Camera::setRenderingCache(osg::Object*) ()
from /usr/lib/libosgUtil.so.80
Can anybody give the reason for it..........

[pommesschranke]

did you read the red box :
what OS (Windows Xp/Vista, Mac etc.) are you running?

the way I use 3 monitors: connect them all to my nvidia GTX650 and stretch one window over all of them.(linux)
do you know the power consumption of you hardware ? ...I'm just curious.

[Johan G]

I moved the post here. He did not see a red box where he originally posted.

Edit: spelling

[Hooray]

Given that it is extremely unlikely that two unrelated users are using the exact same powerful workstation and seeing the exact same compilation error, I must have previously answered this a few days ago, when I said that these seem multi-threading related (aka race conditions), for which the posted backtrace is insufficient - please consider posting a full backtrace for all threads (especially SG/FG here), or using AddressSanitizer - equally, you'll want to provide us with a reproducible set of startup parameters for easily trying to replicate the issue - ideally, such a startup profile should NOT be specific to a single aircraft/location. And for the sake of simplicity it would help to provide a fgfsrc file, as well as pre-recorded flight and/or flight plan (route manager) for reproducing the segfault: viewtopic.php?f=45&t=24959

The code in question triggering the segfault, along with comments, can be seen here: https://gitorious.org/fg/flightgear/sou ... r.cxx#L195

Which is why I suggested to play with different threading modes for testing purposes, so that this can be hopefully tracked down step by step.
Keep in mind that most people don't have the horsepower/CPU cores to actually run into most of FlightGear's threading issues, but someone with your kind of setup is much more likely to actually see those issues.

[Torsten]

while running flightgear3.0. application in 3 window display with 3 K5000 nvidia quadro graphics and 1 DELL precision T7610 PC(64 gb RAM) i am facing this error.

Looks like a multi threading issue to me. When I run FlightGear with multiple screens and multiple cameras, the highes threading mode for OpenSceneGraph that works reliable is CullDrawThreadPerContext while the CullThreadPerCameraDrawThreadPerContext quickly leads to a crash.

You can set the osg threading model upon startup with
--prop:/sim/rendering/multithreading-mode=CullDrawThreadPerContext or add this to your rendering.xml as childs of the <rendering> element:

Code: Select all

     <!--multithreading-mode>AutomaticSelection</multithreading-mode-->
     <!--multithreading-mode>SingleThreaded</multithreading-mode-->
     <!-- multithreading-mode>DrawThreadPerContext</multithreading-mode -->
     <multithreading-mode>CullDrawThreadPerContext</multithreading-mode>
     <!--multithreading-mode>CullThreadPerCameraDrawThreadPerContext</multithreading-mode-->


If it still does not work, try DrawThreadPerContext or even SingleThreaded and see if this helps.

(My full rendering.xml used at fsweekend2014 for six monitors driven from three GTX460 is here.

Torsten

[Hooray]

I already told them the exact same thing a few days ago - but I've added your advice to the wiki now: http://wiki.flightgear.org/Howto:Activa ... ding_modes