Bug 1004093
| Summary: | Xorg hangs on logout when using xdm & the VNC module | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Michael Kolbas <mkolbas> | ||||
| Component: | tigervnc | Assignee: | Tim Waugh <twaugh> | ||||
| Status: | CLOSED ERRATA | QA Contact: | qe-baseos-daemons | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | medium | ||||||
| Version: | 6.4 | CC: | psklenar | ||||
| Target Milestone: | rc | Keywords: | Patch | ||||
| Target Release: | --- | ||||||
| Hardware: | All | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | tigervnc-1.1.0-9.el6 | Doc Type: | Bug Fix | ||||
| Doc Text: |
The vnc Xorg extension could be initialized twice, leading to a busy loop on exit. This has been fixed by backporting a patch to only allow initialization once.
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Story Points: | --- | ||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2014-10-14 04:39:17 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Attachments: |
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The rfb::Configuration linked list has an element whose next element is itself.
Not entirely sure how this happens yet.
(gdb) p *rfb::Configuration::global()
$54 = {name = {buf = 0x1ba58c0 "Global"}, head = 0x7f61c4e9d660,
_next = 0x1ba1080, static global_ = 0x1ba58a0, static server_ = 0x1ba1080,
^^^^^^^^^
static viewer_ = 0x1ba5820}
(gdb) p *rfb::Configuration::global()->_next
$55 = {name = {buf = 0x1ba5210 "Server"}, head = 0x7f61c4e9f3e0,
_next = 0x1ba1080, static global_ = 0x1ba58a0, static server_ = 0x1ba1080,
^^^^^^^^^
static viewer_ = 0x1ba5820}
This is the point at which the list gets looped:
Old value = (rfb::Configuration *) 0x0
New value = (rfb::Configuration *) 0x291c080
0x00007f2700a011e0 in appendConfiguration ()
at ../../../../common/rfb/Configuration.h:152
152 conf->_next = _next; _next = conf;
(gdb) bt
#0 0x00007f2700a011e0 in appendConfiguration ()
at ../../../../common/rfb/Configuration.h:152
#1 enableServerParams () at ../../../../common/rfb/Configuration.h:104
#2 vncExtensionInitWithParams () at xf86vncModule.cc:86
#3 0x00000000004c1e79 in InitExtensions (argc=<value optimized out>,
argv=<value optimized out>) at ../../../mi/miinitext.c:334
#4 0x000000000047c9db in main (argc=4, argv=<value optimized out>,
envp=<value optimized out>) at main.c:208
Created attachment 833286 [details]
tigervnc-extension-init-twice.patch
This seems to stop the problem from happening.
I saw this on x86_64, so removing "32-bit" from the description. Better to use the upstream fix (r5065). *** Bug 983089 has been marked as a duplicate of this bug. *** Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2014-1412.html |
Description of problem: When customer sets DISPLAYMANAGER=xdm in /etc/sysconfig/desktop and also has the native VNC extension for X loaded, logout from gnome hangs when using 32bit RHEL, but customer does not see this issue with x86_64. Though, GDM behaves OK with the VNC extension loaded. Version-Release number of selected component (if applicable): xorg-x11-server-Xorg-1.13.0-11.el6.i686 tigervnc-server-module-1.1.0-5.el6_4.1.i686 (though it may apply to other i686 xorg versions) How reproducible: Always with 32bit RHEL with Xorg and tigervnc-server-module. Hardware can be i686 or x86_64, but issue is seen with 32bit OS. Steps to Reproduce: 1. Install a minimal RHEL 6 32-bit server. 2. yum install tigervnc-server-module xorg-x11-fonts-misc \ xscreensaver xorg-x11-drivers openmotif xorg-x11-server-Xorg \ xorg-x11-xauth xorg-x11-xinit xorg-x11-server-utils xorg-x11-utils \ xdm 3. Edit/create /etc/sysconfig/desktop: DISPLAYMANAGER=xdm 4. Create /etc/X11/xorg.conf.d/vnc.conf: Section "Module" Load "vnc" EndSection 5. Create a test user. 6. Login at the the test user and start runlevel 5 if not there already. 7. Login locally as the test user at the xdm greeter prompt. 8. Logout and observe the hang. Actual results: - xdm / Xorg hangs after logging out. - X server may eventually consume 100% cpu usage until killed. - Never returns to the xdm screen. Expected results: - Should return to the xdm login prompt after logging out. Additional info: - This does not happen with 32bit RHEL and gdm with the native tigervnc-server-module loaded.