Watchdogd currently disables the watchdog when it exits, such as during
rc.shutdown processing. That leaves the system vulnerable to getting hung
or deadlocked during the shutdown part of a reboot. For embedded systems
it's especially important that the hardware watchdog always be active. It
can also be useful for servers that are administered remotely.
The new -x <seconds> option tells watchdogd to program the watchdog with the
given timeout just before exiting. The -x value can be longer or shorter
than the -t normal time value, to allow for various exceptional conditions
at shutdown such as allowing extra time for buffer flushing.
The exit value is also used internally in the "failsafe" handling (which
used to just disable the watchdog), on the theory that if you're using this
option, "safe" means having the watchdog always running, not disabled.
The default is still to disable the watchdog on exit if -x is not specified.
Differential Revision: https://reviews.freebsd.org/D2556 (timed out)
7b4a83b1d0