2.6.21.5 june 30th to july 1st date hang?

["Fortier,Vincent [Montreal]" <Vincent.Fortier1@EC.GC.CA>]

Hi all,

All my servers and workstations running a 2.6.21.5 kernel hanged exactly
when the date shift from june 30th to july 1st.

On my monitoring system every single station running a 2.6.21.5 kernel
stoped responding exactly after midnight on the date shift from June
30th to July 1st.  Although, stations still running 2.6.18 to 2.6.20.11
worked flawlessly.

I first tought there had been an electricity outage but two of my
servers (dell PE 2950 dual-quad core) on UPS in our server room also
hanged:
Jun 30 23:55:01 urpdev1 /USR/SBIN/CRON[31298]: (root) CMD ([ -x
/usr/lib/sysstat/sa1 ] && { [ -r "$DEFAULT" ] && . "$DEFAULT" ; [
"$ENABLED" = "true" ] && exec /usr/lib/sysstat/sa1; })
Jul  3 11:54:03 urpdev1 syslogd 1.4.1#17: restart.

I could not get anything on any of the 20+ consoles...  All the systems
hanged at around the exact same time... When the date shifted from June
30th to July 1st in UTC ...?

Any clue any one?

- vin