Edge condition in idle monitor

Bug #623700 reported by Chris Halse Rogers on 2010-08-25
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Fix Released
gnome-session (Ubuntu)

Bug Description

Binary package hint: gnome-session

While investigating https://bugzilla.gnome.org/show_bug.cgi?id=625374 I've run
across a corner case in the gnome-session idle monitor which also exposes the
Xserver bug referenced in that gnome-screensaver bug.

In _xsync_alarm_set in gs-idle-monitor.c the positive and negative transition
intervals are set to the same value. However, the SYNC extension defines the
positive transition as set when the counter goes from strictly below the
threshold to greater than or equal to the threshold and similarly a negative
transition is triggered when the counter goes form strictly greater than the
threshold to less than or equal to the threshold.

Thus in the current set up there's a chance that the positive transition can
trigger, marking the session as idle, and some user input occur on the same
click so the IDLETIME count will hit the threshold but not go above so the
negative transition will not trigger. Thus the session will not be marked as

The negative transition threshold should be set to 1ms less than the positive
transition to ensure that it always fires.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: gnome-session 2.31.6-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.35-18.24-generic
Uname: Linux 2.6.35-18-generic x86_64
Architecture: amd64
Date: Wed Aug 25 11:13:38 2010
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Alpha amd64 (20100817)
PackageArchitecture: all
 PATH=(custom, user)
SourcePackage: gnome-session

Related branches

Chris Halse Rogers (raof) wrote :
Changed in gnome-session:
status: Unknown → New
tags: added: patch
Changed in gnome-session (Ubuntu):
importance: Undecided → Medium
status: New → Triaged
Changed in gnome-session:
importance: Unknown → Medium
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package gnome-session - 2.32.1-0ubuntu7

gnome-session (2.32.1-0ubuntu7) natty; urgency=low

  * debian/patches/102_fix_negative_transition_in_idletime.patch:
    - Fix race in idle handling which could result in a session being marked
      as idle not being marked as active on user activity. (LP: #623700)
 -- Christopher James Halse Rogers <email address hidden> Tue, 21 Dec 2010 17:25:34 +1100

Changed in gnome-session (Ubuntu):
status: Triaged → Fix Released
Changed in gnome-session:
status: New → Fix Released
To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.