A sysctl hw entropy-injection was added to /etc/rc and has exposed a set of problems.
In automatic performance mode, reading the value also sets it (long story) The setting code on your machine is broken, due to some ACPI table error or parsing of the ACPI tables. This is being looked at, it would be nice if you provide ACPI_DEBUG logs. In /etc/rc change sysctl hw to sysctl hw.sensors, and avoid typing sysctl until this is fixed.
