Comment 53 for bug 1007089

Serge,
  Applications should not be making use of /proc, so any bug related to an application reading /proc and implicitly trusting it's contents is a separate bug. However correcting inaccuracy in /proc is worthy of a bug report.

/sys is the file system for applications to be using as a reliable API, though I don't know if I'd personally trust it's contents either.

Applications must check for failures when returning from system calls and /proc is no different, the validity of information exposed must be validated to catch failures.