RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1673793 - When WaylandEnable=false, starting X11 session from GDM clobbers existing Xvnc display
Summary: When WaylandEnable=false, starting X11 session from GDM clobbers existing Xvn...
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: gdm
Version: 8.0
Hardware: x86_64
OS: Linux
unspecified
unspecified
Target Milestone: rc
: 8.0
Assignee: Ray Strode [halfline]
QA Contact: Desktop QE
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-02-08 06:15 UTC by DRC
Modified: 2024-01-04 23:39 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2021-02-01 07:32:37 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description DRC 2019-02-08 06:15:19 UTC 
Description of problem:
The TurboVNC Server is an Xvnc solution based on Xorg 1.19.6, similar in concept to but with different focus than the TigerVNC Server.  Whenever a TurboVNC Server session is running on Display :1 in RHEL 8 beta, an X11 session started from GDM with WaylandEnable=false will also use Display :1, which prevents the TurboVNC session from working.  For reasons I can't fathom, this doesn't happen with the RHEL 8 build of TigerVNC, even though it appears to be registering its use of Display :1 in exactly the same way (/tmp/.X11-unix/X1 and /tmp/.X1-lock).  I've tried various combinations of enabling and disabling X11 over TCP in the TurboVNC Server, and that didn't seem to make a difference.  I posit that GDM's X display selection logic may not be robust enough, but if there's something we need to be doing to keep GDM from stomping on our display number, then I'm happy to do that.

This may also affect other 3rd-party "X proxy" solutions other than TurboVNC.  I haven't tested that.

Version-Release number of selected component (if applicable):
gdm-3.28.3-9

How reproducible:
Always

Steps to Reproduce:
- Uncomment WaylandEnable=false in /etc/gdm/custom.conf
- Restart GDM
- Leave it sitting at the login prompt
- SSH into the system (or switch to an unused virtual console)
- sudo dnf install https://sourceforge.net/projects/turbovnc/files/2.2.1/turbovnc-2.2.1.x86_64.rpm
- /opt/TurboVNC/bin/vncserver
  (double check that it is listening on Display :1)
- Log in locally using "Standard (X11 display server)" session

Actual results:
The local session uses Display :1

Expected results:
The local session uses Display :2 or another unused X display

Additional info:
Comment 3 RHEL Program Management 2021-02-01 07:32:37 UTC 
After evaluating this issue, there are no plans to address it further or fix it in an upcoming release.  Therefore, it is being closed.  If plans change such that this issue will be fixed in an upcoming release, then the bug can be reopened.
Comment 4 DRC 2024-01-04 23:39:00 UTC 
In case anyone stumbles upon this issue via Google, the workaround is to pass '-listen local' to /opt/TurboVNC/bin/vncserver.  Apparently GDM will choose Display :1 for the X11 session regardless of whether something is listening on the pathname Unix domain socket associated with Display :1 (/tmp/.X11-unix/X1).  However, GDM will choose Display :2 for the X11 session if it detects that something is listening on the abstract Unix domain socket associated with Display :1.  Passing '-listen local' to /opt/TurboVNC/bin/vncserver causes TurboVNC to listen on both the pathname and abstract UDS associated with its X display number.  Just be aware that abstract UDSs have some security concerns, so this workaround may not be a good idea on production TurboVNC hosts.
Note You need to log in before you can comment on or make changes to this bug.