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Bug 623513 - GDM fails to log in if ck-history is too slow
GDM fails to log in if ck-history is too slow
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: gdm (Show other bugs)
All Linux
urgent Severity urgent
: rc
: ---
Assigned To: Ray Strode [halfline]
Depends On:
  Show dependency treegraph
Reported: 2010-08-11 21:39 EDT by Ray Strode [halfline]
Modified: 2010-11-10 15:28 EST (History)
3 users (show)

See Also:
Fixed In Version: gdm-2.30.4-21.el6
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2010-11-10 15:28:21 EST
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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External Trackers
Tracker ID Priority Status Summary Last Updated
GNOME Bugzilla 626564 None None None Never

  None (edit)
Description Ray Strode [halfline] 2010-08-11 21:39:04 EDT
We got an report upstream from Canonical about GDM not working properly for some of their users.  It would never show a login screen for those users.

I spent a few hours debugging the issue with them and determined GDMs "watchdog" handling code (which kills ck-history after a timeout) is missing a line of code to zero out its process id after killing the process.  This missing line prevents GDM from working properly.

This is probably a blocker issue because it means that after months of accumulated use (when the history file gets big) GDM will just stop working.

I've fixed this upstream here:


and got confirmation from several Ubuntu users hit by the issue that the fix works for them.

Artificially reproducing the problem is fairly straight forward:

1) Replace ck-history with a thin shell script wrapper that adds an artificial delay
# mv /usr/bin/ck-history /usr/bin/ck-history.binary

cat > /usr/bin/ck-history << EOF
sleep 5
exec /usr/bin/ck-history.binary "$@"
chmod +x /usr/bin/ck-history

2) Reboot

At this point the GDM greeter will never load
Comment 1 Ray Strode [halfline] 2010-08-12 13:08:15 EDT
This is building now.
Comment 2 Vladimir Benes 2010-08-16 10:39:49 EDT
tested using instructions above .. gdm shows user list even after 5 second delay
Comment 3 Vladimir Benes 2010-08-16 10:40:58 EDT
gdm-2.30.4-21.el6 tested from latest build
Comment 4 releng-rhel@redhat.com 2010-11-10 15:28:21 EST
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.

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