Comment 4 for bug 876387

My workaround is to restore the php5 cron job from 11.04, which does not call fuser:

This is the 11.10 cron job:

09,39 * * * * root [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {} 2>/dev/null \; -delete

And this is the 11.04 cron job:

09,39 * * * * root [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) -delete

We think fuser was added to cater for some edge case of process not closing the session file, but was never tested with a large number of sessions.

I posted this solution yesterday on the thread: http://ubuntuforums.org/showthread.php?p=11355965