@@ -39,6 +39,10 @@
static DEFINE_IDA(watchdog_ida);
+static int stop_on_reboot = -1;
+module_param(stop_on_reboot, int, 0444);
+MODULE_PARM_DESC(stop_on_reboot, "Stop watchdogs on reboot (0=keep watching, 1=stop)");
+
/*
* Deferred Registration infrastructure.
*
@@ -254,6 +258,14 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
}
}
+ /* Module parameter to force watchdog policy on reboot. */
+ if (stop_on_reboot != -1) {
+ if (stop_on_reboot)
+ set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
+ else
+ clear_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
+ }
+
if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
Many watchdog drivers use watchdog_stop_on_reboot() helper in order to stop the watchdog on system reboot. Unfortunately, this logic is coded in driver's probe function and doesn't allows user to decide what to do during shutdown/reboot. On the other side, Xen and Qemu watchdog drivers (xen_wdt and i6300esb) may be configured to either send NMI or turn off/reboot VM as the watchdog action. As the kernel may stuck at any state, sending NMIs can't reliably reboot the VM. At Arista, we benefited from the following set-up: the emulated watchdogs trigger VM reset and softdog is set to catch less severe conditions to generate vmcore. Just before reboot watchdog's timeout is increased to some good-enough value (3 mins). That keeps watchdog always running and guarantees that VM doesn't stuck. Provide new stop_on_reboot module parameter to let user control watchdog's reboot policy. Cc: Guenter Roeck <linux@roeck-us.net> Cc: Wim Van Sebroeck <wim@linux-watchdog.org> Cc: linux-watchdog@vger.kernel.org Signed-off-by: Dmitry Safonov <dima@arista.com> --- Changes: v3: Make module parameter read-only in runtime (Thanks Guenter for spotting the typo!) v2: Add module parameter instead of ioctl() drivers/watchdog/watchdog_core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)