In addition to the patched bugs, several panics were discovered by NCC that
can be triggered by root or users with the usermount option set. These bugs
are not getting patched because we believe they are only the tip of the
iceberg. The mount system call exposes too much code to userland to be
As remediation, it's recommended to disable usermount. For the forthcoming 6.0
release, the usermount option will be removed.