Bug 966434 - gnome-screensaver crashes when running in VNC
gnome-screensaver crashes when running in VNC
Product: Fedora
Classification: Fedora
Component: gnome-screensaver (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Ray Strode [halfline]
Fedora Extras Quality Assurance
Depends On:
  Show dependency treegraph
Reported: 2013-05-23 05:39 EDT by Albert Flügel
Modified: 2013-08-01 06:38 EDT (History)
2 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2013-08-01 06:38:23 EDT
Type: Bug
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
Fix or workaround calling a function via a pointer, that is NULL (909 bytes, patch)
2013-05-23 05:39 EDT, Albert Flügel
no flags Details | Diff

  None (edit)
Description Albert Flügel 2013-05-23 05:39:49 EDT
Created attachment 752061 [details]
Fix or workaround calling a function via a pointer, that is NULL

Description of problem:
When a Gnome Session (whether fallback or not does not matter) is running in a VNC server, Locking the screen does not work and the window manager becomes somewhat dysfunctional

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

How reproducible:
Start a vnc server, connect with vncviewer, try to lock the screen
or let it lock automatically

Steps to Reproduce:
1. prompt# vncserver -extension RANDR
2. prompt# vncviewer :1
   (or whatever session number is output by vncserver)
3. Within the session select in the top menu under the user's name on the right "Lock screen"

Actual results:
Display starts to darken, but then the normal desktop is visible again and the window manager seems to be canceled somehow. In the top bar a message appears "gnome-screensaver crashed ..."

Expected results:
Screen is locked and can be unlocked again entering the password

Additional info:
The gnome-screensaver gets SIGSEGV:
In src/gs-fade.c in 2 lines a function is called via a pointer like this:
fade->priv->screen_priv[i].fade_finish(fade, i);
It seems, when running in VNC, there's no respective capability in the server, so the entire structure fade->priv->screen_priv[i] is zero, so is
The attached patch adds a check: if fade->priv->screen_priv[i].fade_finish
is NULL, the function is not called.
Frankly i don't know, if this is really a fix or only a workaround. The
maintainer must judge.
However. One more time adding a fancy but superfluous feature introduced a new annoying bug.
Comment 1 Fedora End Of Life 2013-07-03 23:16:20 EDT
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Comment 2 Fedora End Of Life 2013-08-01 06:38:27 EDT
Fedora 17 changed to end-of-life (EOL) status on 2013-07-30. Fedora 17 is 
no longer maintained, which means that it will not receive any further 
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