[CentOS] tigervnc-server-module crashes after EL 6.3 update

Tue Aug 14 22:23:28 UTC 2012
Cal Webster <cwebster at ec.rr.com>

We began experiencing failed vnc connections to the console display on
servers that have been updated to EL 6.3. No such failures have occurred
on similar connections to EL 6.2 servers.

On the client machine a normal vncviewer display appears with the
expected graphical login until the mouse pointer is moved within the
boundaries of the vncviewer window. At this point the window closes and
an error message appears in both a pop-up window and in the terminal
window in which the session was initiated stating "read: Connection
reset by peer (104)".

On the server end, a core dump is generated and a abrt bug report is

Aug 14 11:00:30 jato2 abrt[11411]: File '/usr/bin/Xorg' seems to be
Aug 14 11:00:30 jato2 abrt[11411]: Saved core dump of pid 7892
(/usr/bin/Xorg) to /var/spool/abrt/ccpp-2012-08-14-11:00:30-7892
(42041344 bytes)
Aug 14 11:00:30 jato2 abrtd: Directory 'ccpp-2012-08-14-11:00:30-7892'
creation detected

This bug has been reported in the CentOS bug tracker here:

0005824: tigervnc-server-module keep crashing

However, this appears to be a bug upstream. The source RPM provided with
CentOS is identical to that of upstream with no modifications. Also,
there is an upstream bug reported that appears to have the same
symptoms. I have added a comment to the upstream bug report (listed
below) if anyone wishes to see the details.

tigervnc-server-module crashes with dual screen setup

We have verified that rebuilding the unmodified source RPM for tigervnc
produces a tigervnc-server-module RPM that does not suffer from this

Removing the original tigervnc-server-module package and replacing it
with the rebuilt one fixes the problem.

I've duplicated the problem on 2 EL 6.3 x86_64 single-head display
machines and have verified the fix.

Tomorrow, I'll duplicate the problem on a dual-head x86_64 machine that
currently still works after updating to EL 6.2 then confirm the the fix.