DRC, Thanks very much for taking the time to investigate this, even though you suspected it was a TigerVNC bug, not a TurboVNC bug, and you were correct.
It looks like upgrading from CentOS 6.2 to 6.3 won't help (I still won't get a recent enough version of TigerVNC server). But a colleague of mine has recently installed TigerVNC server 1.2.0 from source successfully on a CentOS 6.2 machine, so I should be able to just do the same thing on the machine which this bug occurred on. Regards, James On 27/09/2012, at 5:41 PM, DRC wrote: > This is indeed a TigerVNC bug of sorts. The older server encodes blank > cursors using the RFB X11 cursor encoding, but it was sending a non-zero > hotspot which, when passed into XCreatePixmapCursor in the TurboVNC > Viewer, generated a BadMatch (apparently it's an error to use a non-zero > hotspot when you pass an empty Pixmap to that function.) Whenever the > failure occurs, the server gets into a bad state somehow and stops > sending anything to TurboVNC viewers (but oddly enough, I could connect > with a TigerVNC viewer and free it up.) The latest TigerVNC server > (1.2) doesn't suffer from this issue. > > I worked around the issue by setting the hotspot to 0,0 in the Unix > TurboVNC Viewer whenever an empty cursor is received from the server. > > When using the Windows TurboVNC Viewer, it's also possible to crash the > viewer using the same drag 'n' drop technique, assuming that cursor > shape updates are not enabled (that is, the cursor is being rendered on > the server.) In that case, the server apparently renders the empty > cursor and tries to encode that framebuffer update in a way that isn't > kosher. Since enabling cursor shape updates works around the issue on > Windows, as does upgrading to a newer TigerVNC Server, I'm not going to > worry about it further. > > > On 9/26/12 1:39 AM, James Wettenhall wrote: >> DRC, >> >> On 24/09/2012, at 1:01 PM, DRC wrote: >> >>> Does the same thing happen when using a different viewer? >> >> No, we can't reproduce the drag and drop problem using TigerVNC viewer and >> TigerVNC server >> >>> Does the same >>> thing happen when using the TurboVNC server? >> >> No, we can't reproduce the drag and drop problem using TurboVNC viewer and >> TurboVNC server either. >> >> And when we switch both, i.e. use TigerVNC viewer with TurboVNC server, we >> still can't reproduce the problem. >> >> We can only reproduce it when using TurboVNC viewer with TigerVNC server. >> >> Changing browsers (from Firefox to Google Chrome) didn't make a difference. >> >> Whilst we can't give you login credentials to the webpage in question >> (within which we can reproduce the drag and drop crashing problem), we could >> send you a saved copy of that webpage. All of the links would be broken >> because you wouldn't be properly logged in, but you could still demonstrate >> dragging one of the links within that page. I tried running the webpage >> through the W3C HTML validator, and it certainly has some HTML errors, (and >> probably Javascript and CSS errors too). It is part of a secure portal from >> an apparently reputable vendor of firewalls and network infrastructure. >> >> Or I could give you temporary access to a temporary virtual machine on the >> cloud with a public facing IP address on which we can demonstrate the >> problem if that helps. >> >> Dragging and dropping was not required to use the web application, but >> Geoffrey accidentally dragged a hyperlink slightly while clicking on it, >> which triggered the crash. >> >> Cheers, >> James >> >>> If the answers to the above are "yes" and "no", then it isn't our bug. >>> It's TigerVNC's, and the first thing they'll tell you is "use a newer >>> release." Of course, the problem is that Red Hat has frozen their >>> supplied version of TigerVNC at 1.1, so newer releases of TigerVNC are >>> not supported by Red Hat, but older releases are not supported by The >>> TigerVNC Project. >> >> >> >> >>> >>> >>> On 9/23/12 9:36 PM, Geoffrey Kong wrote: >>>> Hi all, >>>> >>>> The VNC instances crashed whenever I did a click-and-drag, e.g. from >>>> within Firefox, with the following error message. >>>> >>>> CleanupXErrorHandler called >>>> X Error of failed request: BadMatch (invalid parameter attributes) >>>> Major opcode of failed request: 93 (X_CreateCursor) >>>> Serial number of failed request: 4067 >>>> Current serial number in output stream: 4071 >>>> >>>> We are using TurboVNC 1.1 as client on Mac OS X and TigerVNC 1.0.90 as >>>> server on CentOS 6.2 Linux. >>>> >>>> Would anyone know what the problem is? >>>> >>>> Thanks, >>>> Geoffrey Kong >>> >>> ------------------------------------------------------------------------------ >>> Live Security Virtual Conference >>> Exclusive live event will cover all the ways today's security and >>> threat landscape has changed and how IT managers can respond. Discussions >>> will include endpoint security, mobile security and the latest in malware >>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >>> _______________________________________________ >>> VirtualGL-Users mailing list >>> VirtualGL-Users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/virtualgl-users >> >> >> ------------------------------------------------------------------------------ >> Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. Discussions >> will include endpoint security, mobile security and the latest in malware >> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >> _______________________________________________ >> VirtualGL-Users mailing list >> VirtualGL-Users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/virtualgl-users >> > > ------------------------------------------------------------------------------ > Everyone hates slow websites. So do we. > Make your web apps faster with AppDynamics > Download AppDynamics Lite for free today: > http://ad.doubleclick.net/clk;258768047;13503038;j? > http://info.appdynamics.com/FreeJavaPerformanceDownload.html > _______________________________________________ > VirtualGL-Users mailing list > VirtualGL-Users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/virtualgl-users ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. 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