Add a new "dump" pretimeout governor that triggers a backtrace of all
CPUs (via trigger_all_cpu_backtrace()) to the kernel log buffer. This
provides diagnostic information right before the hardware watchdog
fires.
In addition, update the WATCHDOG_PRETIMEOUT_GOV_SEL Kconfig logic to
fall back to the "panic" governor only when both "noop" and "dump"
governors are disabled.
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20260707102105.3600275-1-tzungbi@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>