ps not working as expected

[Ron Yorston]

I'm seeing different results if I run 'ps ax' as root and as an ordinary
user.  Some processes don't appear in the listing for the ordinary user.
Running under strace shows that ps is failing to open /proc/NNN/stat for
these processes.  'ls -Z' shows that these processes (and only these
processes) have SystemLow-SystemHigh on their stat files.  If I run with
selinux=0 ps behaves as expected.

This is an fc5t3 system with all recent updates.  Kernel 2.6.15-1.1977_FC5.

Ron