Hello,

I work on a rendering plug-in which displays buckets in the Render View through a multithread queue, and sometimes, when I work in IPR mode, Maya crash (only on the Linux version; no probmes with the Windows one).
maya.bin: xcb_lock.c:77: _XGetXCBBuffer: Assertion `((int) ((xcb_req) - (dpy->request)) >= 0)’ failed.

Here is the trace :

****
* signal caught: SIGABRT—Abnormal process abort
* major page faults: 0
* virtual memory size: 873 MB
* resident set size: 272 MB
* backtrace:
* 1 /lib64/libpthread.so.0
* *
* 2 /lib64/libc.so.6
* extern “C” gsignal()
*
* 3 /lib64/libc.so.6
* extern “C” abort()
*
* 4 /lib64/libc.so.6
* extern “C” __assert_fail()
*
* 5 /usr/lib64/libX11.so.6
* *
* 6 /usr/lib64/libX11.so.6
* extern “C” _XSend()
*
* 7 /usr/lib64/libX11.so.6
* extern “C” _XEventsQueued()
*
* 8 /usr/lib64/libX11.so.6
* extern “C” XEventsQueued()
*
* 9 /usr/lib64/libXt.so.6
* extern “C” XtAppNextEvent()
*
* 10 /s/apps/maya/maya2009-x64/lib/libExtensionLayer.so
* TeventHandler::processXEvent(bool)
*
* 11 /s/apps/maya/maya2009-x64/lib/libExtensionLayer.so
* TunixEventHandler::handleEvents(Tresponder*)
*
* 12 /s/apps/maya/maya2009-x64/lib/libExtensionLayer.so
* Tapplication::start()
*
* 13 /s/apps/maya/maya2009-x64/bin/maya.bin
* *
* 14 /s/apps/maya/maya2009-x64/bin/maya.bin
* *
* 15 /lib64/libc.so.6
* extern “C” __libc_start_main()
*
* 16 /s/apps/maya/maya2009-x64/bin/maya.bin
* extern “C” __gxx_personality_v0()
****

Maya 2009 / SuSE 11.1

Thanks for help.

For Maya, one needs to be careful with threads, and X threads in particular.  Maya does not call XThreadInit() by default.  if you are using multiple X threads

there have also been some reported instances of problems with libX11.so with xcb support interacting badly with Maya.  recompiling libX11.so without xcb support appears to fix those problems.

Hello,

Sorry for the delay (I expected to be informed of any answer), and thank you for your answer.

Actually, I use for my queue a producer/consumer model, with n producers (multithreaded) and 1 consumer (to send the buckets to the Maya API). So I don’t use multithread with Maya. It seems that it is maya which tries internally to do some multithreading.