drscheme crashes after upgrade to libx11-6 2:1.1.1-1ubuntu1

[Roshan Shariff]

Binary package hint: drscheme

The upgrade to libx11-6 pulled in libxcb1 1.0-1.1 as an additional dependancy. Following this upgrade, drscheme crashes shortly after startup with this message:

$ drscheme
mred: xcb_xlib.c:41: xcb_xlib_lock: Assertion `!c->xlib.lock' failed.
Aborted (core dumped)

This bug has been reported in Debian (#409197) and a similar bug occurs in Java (Ubuntu #86103). This type of crash is mentioned in debian-devel-announce at http://people.debian.org/~terpstra/message/20061127.041128.8a08d75f.en.html which says the message indicates "that a caller attempted to lock the display while already locked".

A backtrace is attached to the Debian drscheme bug mentioned above.

[Roshan Shariff (roshan.shariff)]

I've opened a bug report upstream on the PLT bugtracker at http://bugs.plt-scheme.org/query/?cmd=view&pr=8547 which contains some more detail and the location of the buggy code.

Also, it appears that Debian #409197 is not exactly the same bug, but it is in the same class of problems.

[John Dong (jdong)]

Confirmed -- happens here, too.

[Bastian Holst (bastianholst)]

This happens for Java and Python programmes, too. I think libxcb1 1.0-1.1 is the package which is damaged.

[Roshan Shariff (roshan.shariff)]

libxcb1 isn't actually "damaged", as indicated by [http://people.debian.org/~terpstra/message/20061127.041128.8a08d75f.en.html]. It simply crashes now to indicate a double-lock or double-unlock in the program.

In fact, this particular bug in drscheme has been fixed in upstream SVN but I don't know when they're going to make a release incorporating the fix.

[Rthaduthd Anthnhkrc (nthnuekeu-deactivatedaccount)]

Confirmed here too. DrScheme is used in quite a lot of CS courses around the world.

[Roshan Shariff (roshan.shariff)]

This bug has been worked around in libxcb (see Ubuntu #86103). Hopefully by the time Feisty+1 rolls around and the workaround is removed, upstream will release the new version of DrScheme incorporating the fix.

[psernetz (patrick-sernetz-com)]

Happens although on my side..
Trying to run .. Neverwinter Nights... results in ..

nwmain: ../../src/xcb_lock.c:62: _XGetXCBBuffer: Assertion `((int) ((xcb_req) - (dpy->request)) >= 0)' failed.
Aborted (core dumped)

[Ryba (sepatel)]

The latest update seems to have fixed my java programs which were breaking but Neverwinter Nights still seems to be broken.

Is there an environment variable or something we can do to toggle the assert so that for certain known to be broken applications which will likely never in their life be fixed (a.k.a Neverwinter Nights) will run?

[Ryba (sepatel)]

My fix (from googling this problem) is to install the following

Finding old packages in Launchpad is really annoying:

http://librarian.launchpad.net/5509177/libx11-6_1.0.3-4ubuntu1_i386.deb
http://librarian.launchpad.net/5509176/libx11-data_1.0.3-4ubuntu1_all.deb

Then doing a "sudo dpkg -i libx11*deb"

Everything works great now. Basically downgraded the app to a version that didn't do the assertion checks :)

[Steve Kowalik (stevenk)]

This has been fixed properly in Ubuntu Gutsy, with version 360 of drscheme uploaded.

[Loom (loom)]

It's back: https://bugs.launchpad.net/ubuntu/+source/drscheme/+bug/172517 (for me when I upgraded from gutsy to hardy alpha)

[Cristian Aravena Romero (caravena)]

Update of Gutsy to Hardy.