how to spot the process in block mode ?

[zs_hzh]

while checking system by vmstat , it appear 1 blocked process in the list for always , but how do i know which process ?

CGAPP1:/root #ps -efl |awk '{print $2}'|sort |uniq -c
19 R
95 S
1 Z
CGAPP1:/root #vmstat 2 10
procs memory page faults cpu
r b w avm free re at pi po fr de sr in sy cs us sy id
1 1 0 52194 1570611 16 4 0 0 0 0 1 436 1106 69 0 0 100
1 1 0 52194 1570534 60 4 0 0 0 0 0 434 942 62 0 0 100

some says state D , but there isn't any

and free memory is efficient , how do i know which one and why ?

thanks