can the idle value of /proc/stat decrease?

[xuqiang (M)]

Our recent test shows that the idle value of /proc/stat can decrease.
Is this an unreported bug? or it has been reported and the solution is 
waiting to get merged.

The results of the two readings from /proc/stat are shown as below, the 
interval between the two readings is 150 ms:

cat /proc/stat
cpu0 5536 10 14160 4118960 0 0 227128 0 0 0

cat /proc/stat
cpu0 5536 10 14160 4118959 0 0 227143 0 0 0