memory corruption, crashes in xrandr - try to add a "sleep 1" between the xrandr calls in your script.

if your sleep version is nifty enough, you can probably use smaller values than a second which should be sufficient as well.

otherwise try whether
xrandr --output VGA1 --pos 0x0 --mode 1920x1080 --output HDMI1 --pos 1920x0 --mode 1920x1080  --noprimary
works

*** Bug 293648 has been marked as a duplicate of this bug. ***

Thanks for marking my report as a duplicate of this one.
In my case, this happens only for remote logins (every time), not for local login.

Kwin crashes on even this simple xrandr invocation:
xrandr --output HDMI1 --pos 1920x0

Even if this is a problem with xrandr, maybe kwin should still handle it more gracefully than crashing.  Would be great if I could use a dual monitor setup with KDE without getting crashes every time I start up.

(In reply to comment #4)
> Kwin crashes on even this simple xrandr invocation:
> xrandr --output HDMI1 --pos 1920x0
Does it only happen for the HDMI device and/or only for the position adjustment?

> Even if this is a problem with xrandr, maybe kwin should still handle it more
> gracefully than crashing. 
It's not a problem with the cli tool but with the extension, ie libXrandr - or one of its deps (libX11, libc)
Whenever you find a way to avoid segfaults in sublying library calls:
DO NOT TELL ANYONE!
Write a book and sell it. You'll become a millionaire ;-)

> Would be great if I could use a dual monitor setup with KDE without getting crashes every time I start up.

- Get an update for libXRandr, libX11 or libc (though this may also be just a downstream issue, ie. a wonky patch from your distro. The only two reports are from the very same distro & version)
- Try to deactivate "Display Management change Monitor" in "kcmshell4 kded" (but that is just a wild guess about timing, i doubt it solves anything)

Created attachment 70035 [details]
New crash information added by DrKonqi

kwin (4.8.1 (4.8.1)) on KDE Platform 4.8.1 (4.8.1) using Qt 4.8.0

- What I was doing when the application crashed:

after upgrading to ubuntu 12.04 beta 2, i've experienced this crash at startup

-- Backtrace (Reduced):
#6  __GI___libc_free (mem=0x1) at malloc.c:2968
[...]
#8  0x00007ff29bbc5819 in XFree () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#9  0x00007ff29b76d2ee in XRRUpdateConfiguration () from /usr/lib/x86_64-linux-gnu/libXrandr.so.2
#10 0x00007ff29e4b8750 in KWin::Workspace::workspaceEvent (this=0x24d5720, e=0x7fffc9b67000) at ../../kwin/events.cpp:460
#11 0x00007ff29e4a9fa8 in KWin::Application::x11EventFilter (this=0x7fffc9b67310, e=0x7fffc9b67000) at ../../kwin/main.cpp:359

*** Bug 298304 has been marked as a duplicate of this bug. ***

*** Bug 298370 has been marked as a duplicate of this bug. ***

Hi Martin,

Can you please tell me what package has this bug been resolved in upstream? I would like to try upgrading something on my system to a fixed version and to ensure that the bug has disappeared. We are in desperate need to get kwin working under NX and are willing to actively help with testing!

Is there a possible workaround for this bug? I am not running xrandr myself, so would I have to try an updated libXrandr.so.2?

Thanks!
Iordan

(In reply to comment #9)
> Can you please tell me what package has this bug been resolved in upstream?
"resolved upstream" actually just means "bug in used library, not our problem"
afaics however only ubuntu and only this very version seems affected, what could point a downstream (bad distro patch) bug

OK, I've reported this bug to Ubuntu as well. Anybody who is affected should also go and raise the heat on the bug (say that you are affected or create duplicate bugs) if you are desperate to fix this.

Here is a link to my bug-report:
https://bugs.launchpad.net/ubuntu/+source/libx11/+bug/985202

*** Bug 298845 has been marked as a duplicate of this bug. ***

*** Bug 299728 has been marked as a duplicate of this bug. ***

*** Bug 300174 has been marked as a duplicate of this bug. ***

*** Bug 300234 has been marked as a duplicate of this bug. ***

*** Bug 300515 has been marked as a duplicate of this bug. ***

*** Bug 301388 has been marked as a duplicate of this bug. ***

*** Bug 302191 has been marked as a duplicate of this bug. ***

Created attachment 72617 [details]
New crash information added by DrKonqi

kwin (4.8.4 (4.8.4)) on KDE Platform 4.8.4 (4.8.4) using Qt 4.8.1

- What I was doing when the application crashed:

Brand new install of Kubuntu 12.04.  Same behavior as others, Kwin crashes right after a new NX session is opened.

-- Backtrace (Reduced):
#8  0xb67c4f9b in XFree (data=0x1) at ../../src/XlibInt.c:1701
#9  0xb6771c76 in XRRUpdateConfiguration (event=0xbfeec42c) at ../../src/Xrandr.c:446
#10 0xb76585c7 in KWin::Workspace::workspaceEvent (this=0x891e430, e=0xbfeec42c) at ../../kwin/events.cpp:460
#11 0xb7648842 in KWin::Application::x11EventFilter (this=0xbfeec678, e=0xbfeec42c) at ../../kwin/main.cpp:359
#12 0xb54cf534 in qt_x11EventFilter (ev=0xbfeec42c) at kernel/qapplication_x11.cpp:441

Created attachment 73372 [details]
New crash information added by DrKonqi

kwin (4.9.00) on KDE Platform 4.9.00 using Qt 4.8.1

I just run into a similar crash while logging in to my desktop via an X11 thin client.

-- Backtrace (Reduced):
#6  mUSABLe (mem=0x1) at malloc.c:4651
#7  __malloc_usable_size (m=0x1) at malloc.c:3379
[...]
#10 0x00007f335399d819 in XFree (data=<optimized out>) at ../../src/XlibInt.c:1701
#11 0x00007f33535452ee in XRRUpdateConfiguration (event=0x7fffce3726d0) at ../../src/Xrandr.c:446
#12 0x00007f3355c53736 in KWin::Workspace::workspaceEvent (this=0x1f6ed80, e=0x7fffce3726d0) at ../../kwin/events.cpp:461

*** Bug 307023 has been marked as a duplicate of this bug. ***

*** Bug 307675 has been marked as a duplicate of this bug. ***

*** Bug 308535 has been marked as a duplicate of this bug. ***

*** Bug 309268 has been marked as a duplicate of this bug. ***

*** Bug 310115 has been marked as a duplicate of this bug. ***

Created attachment 76184 [details]
New crash information added by DrKonqi

kwin (4.9.5) on KDE Platform 4.9.5 using Qt 4.8.2

- What I was doing when the application crashed:
 
I  started the NX session and KWin crashed.

-- Backtrace (Reduced):
#6  mUSABLe (mem=0x1) at malloc.c:4651
#7  __malloc_usable_size (m=0x1) at malloc.c:3379
[...]
#10 0x00007f61b52ab819 in XFree () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#11 0x00007f61b4e532ee in XRRUpdateConfiguration () from /usr/lib/x86_64-linux-gnu/libXrandr.so.2
[...]
#14 0x00007f61b2181aa5 in qt_x11EventFilter (ev=0x7fff48df4f70) at kernel/qapplication_x11.cpp:441

Is this bug really resolved? If so, in which version of KDE was it done?

(In reply to comment #27)
> Is this bug really resolved? If so, in which version of KDE was it done?
Please see comment #10

*** Bug 315450 has been marked as a duplicate of this bug. ***

last dupe is OpenSuSE - no more ubuntu-only issue

> last dupe is OpenSuSE - no more ubuntu-only issue
and it's the 12.3 release to get out quite soon. Seems like they updated the 
library...

... Unlikely being libxrandr then - bug appeard between 11.10 and 12.04 in ubuntu - both shipping 1.3.2 while current 12.10 has 1.4.0

SuSE 12.2 had 1.3.2 as well.

And Arch is on 1.4.0 since 2012-07-29

The suse trace however has lines. gonna check them tonight ;-)

Anybody who
- can cause this for sure
- can compile and test a patch

please raise hands.

I can reproduce this 100% of the time on Kubuntu 12.10 (before 12.04). It happens every time I connect to my machine via NX client and also once connected every time I change with the NX window resolution (e.g. do fullscreen). I you can help me with the compile part (haven't compile kde before) I can test.

(In reply to comment #34)
> haven't compile kde before

Thanks alot. Let's first see whether someone who can "just do" pops up, otherwise you'll learn how to compile ;-)

I can both trigger this and compile KDE. At your service... :-)

Ok, patch is possibly trivial:
in events.cpp, find XRRUpdateConfiguration(e); (~line 468) and inject

XSync(display(), false);

right after.

I'll explain the guess if it works =)

Patched the file:

--------------------
diff --git a/kwin/events.cpp b/kwin/events.cpp
index 281f9e7..f5492e7 100644
--- a/kwin/events.cpp
+++ b/kwin/events.cpp
@@ -462,6 +462,7 @@ bool Workspace::workspaceEvent(XEvent * e)
     default:
         if (e->type == Extensions::randrNotifyEvent() && Extensions::randrAvailable()) {
             XRRUpdateConfiguration(e);
+           XSync(display(),false);
             if (compositing()) {
                 // desktopResized() should take care of when the size or
                 // shape of the desktop has changed, but we also want to
--------------------

Then cmake, make and make install. Afterwards kwin --replace.

Unfortunally, KWin stills crashes when unplugging:

--------------------

Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f16586f5780 (LWP 15862))]

Thread 3 (Thread 0x7f1636ffd700 (LWP 15891)):
#0  0x00007f1652b1a964 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f16549c7307 in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f1654cd4660 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007f16549c7339 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007f1652b16e0f in start_thread () from /lib64/libpthread.so.0
#4  0x00007f1650ab77dd in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f162ffff700 (LWP 15893)):
#0  0x00007f1652b1a964 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f16349b7543 in ?? () from /usr/lib64/dri/r600_dri.so
#2  0x00007f1652b16e0f in start_thread () from /lib64/libpthread.so.0
#3  0x00007f1650ab77dd in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f16586f5780 (LWP 15862)):
[KCrash Handler]
#5  0x00007f1650a4d634 in free () from /lib64/libc.so.6
#6  0x00007f1656bc3089 in XFree (data=<optimized out>) at XlibInt.c:1701
#7  0x00007f1655f2fad6 in XRRUpdateConfiguration (event=<optimized out>) at Xrandr.c:509
#8  0x00007f165824c998 in KWin::Workspace::workspaceEvent (this=0xa3a8e0, e=0x7fffe2452380) at /home/ademmer/Source/own/KDE/kde-workspace/kwin/events.cpp:464
#9  0x00007f165823e2e8 in KWin::Application::x11EventFilter (this=0x7fffe24528e0, e=0x7fffe2452380) at /home/ademmer/Source/own/KDE/kde-workspace/kwin/main.cpp:362
#10 0x00007f16520a2bfc in qt_x11EventFilter (ev=0x7fffe2452380) at kernel/qapplication_x11.cpp:435
#11 qt_x11EventFilter (ev=0x7fffe2452380) at kernel/qapplication_x11.cpp:423
#12 0x00007f16520b01eb in QApplication::x11ProcessEvent (this=0x7fffe24528e0, event=0x7fffe2452380) at kernel/qapplication_x11.cpp:3362
#13 0x00007f16520d79d9 in QEventDispatcherX11::processEvents (this=0x8b8fe0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#14 0x00007f1652ea79bf in QEventLoop::processEvents (this=this@entry=0x7fffe24525f0, flags=...) at kernel/qeventloop.cpp:149
#15 0x00007f1652ea7c48 in QEventLoop::exec (this=0x7fffe24525f0, flags=...) at kernel/qeventloop.cpp:204
#16 0x00007f1652eac8e8 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1218
#17 0x00007f165824089a in kdemain (argc=3, argv=0x7fffe2452a28) at /home/ademmer/Source/own/KDE/kde-workspace/kwin/main.cpp:537
#18 0x00007f16509f0a15 in __libc_start_main () from /lib64/libc.so.6
#19 0x00000000004009c1 in _start () at ../sysdeps/x86_64/start.S:123

One clarification: My original bug report (Bug 309268) told that the crashes would appear both on plugging and unplugging. In fact, I am only to trigger the crash on unplugging an external display.

blast.

+           XSync(display(),false); // voodoo
+           if (qApp->desktop()->screenCount()) // possible cause
                XRRUpdateConfiguration(e);
+           XSync(display(),false); // because xrandr states "should do that"

but that should crash before (in xrandr) so i do not really believe it's gonna work (unless the source lines are padded in your compilation)

Not sure whether I got this right...

------------

diff --git a/kwin/events.cpp b/kwin/events.cpp
index 281f9e7..05cecc3 100644
--- a/kwin/events.cpp
+++ b/kwin/events.cpp
@@ -461,7 +461,10 @@ bool Workspace::workspaceEvent(XEvent * e)
         break;
     default:
         if (e->type == Extensions::randrNotifyEvent() && Extensions::randrAvailable()) {
-            XRRUpdateConfiguration(e);
+           XSync(display(),false);
+           if (qApp->desktop()->screenCount()) // possible cause
+               XRRUpdateConfiguration(e);
+           XSync(display(),false); // because xrandr states "should do that"
             if (compositing()) {
                 // desktopResized() should take care of when the size or
                 // shape of the desktop has changed, but we also want to

------------

Was this your suggestion? Still crashing on unplug though... :(

*** Bug 315840 has been marked as a duplicate of this bug. ***

*** Bug 316800 has been marked as a duplicate of this bug. ***

Hello fedora.
Xrandr portion crashing is btw:

    /*
     * so the next time someone wants some data, it will be fetched;
     * it might be better to force the round trip immediately, but
     * I dislike pounding the server simultaneously when not necessary
     */
    if (xrri->config[snum] != NULL) {
	XFree (xrri->config[snum]);
^^^^^^^^^^^^^^^^^^^^^^^^^ <-  this line
	xrri->config[snum] = NULL;
    }