View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0014022||CentOS-7||gdm||public||2017-10-16 15:43||2018-01-26 09:34|
|Target Version||Fixed in Version|
|Summary||0014022: GDM crashes with XDMCP when locking screen|
|Description||I have enabled XDMCP in GDM and set up Xvnc to use it.|
I can log in fine via VNC to the Xvnc server using the GDM with XDMCP, but when the screen is locked I cannot unlock the screen. An attempt to unlock the screen crashes gdm. Also, after this occurs I also have trouble simple login in, gdm often crashes as well.
According to ABRT, gdm crashes in _int_malloc() within libc, so it looks like gdm is doing some heap corruption.
|Steps To Reproduce||The following are simple steps to reproduce the issue (simpler than setting up Xvnc with systemd).|
1. Enable XDMCP in gdm in /etc/gdm/custom.conf
2. Restart gdm with "systemctl restart gdm.service"
3. Install tigervnc-server
4. Open port 5901 on the firewall: firewall-cmd --add-port=5901/tcp
5. Setup a VNC password with: vncpassword
6. Log in as a regular user via SSH and run
/usr/bin/Xvnc :1 -query localhost -once -geometry 1024x768 passwordfile=$HOME/.vnc/passwd
7. Connect from a VNC client on display :1
8. Lock the screen of the VNC session
9. Unlock the screen, GDM will crash just after typing the password
|Additional Information||GDM version: gdm-3.22.3-12.el7.x86_64|
Apparently this is just this bug: https://bugzilla.gnome.org/show_bug.cgi?id=786656 and the fix is https://git.gnome.org/browse/gdm/commit/?id=42ae130
I got the sources from the debuginfo and the above problem is there. I also attached gdb and confirmed that it is doing a free of a dangling pointer.
The Red Hat bug https://bugzilla.redhat.com/show_bug.cgi?id=1500788 could also be related.
|Tags||No tags attached.|