[PATCH AUTOSEL 5.13 19/29] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate

From: Sasha Levin
Date: Sat Sep 11 2021 - 09:15:42 EST

From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

[ Upstream commit dbe80cf471f940db3063197b7adb1169f89be9ed ]

We must not pet a running watchdog when handle_boot_enabled is off
because this will kick off automatic triggering before userland is
running, defeating the purpose of the handle_boot_enabled control.
Furthermore, don't ping in case watchdog_set_last_hw_keepalive was
called incorrectly when the hardware watchdog is actually not running.

Fixed: cef9572e9af3 ("watchdog: add support for adjusting last known HW keepalive time")
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/93d56386-6e37-060b-55ce-84de8cde535f@xxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/watchdog/watchdog_dev.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 2946f3a63110..2ee017442dfc 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -1164,7 +1164,10 @@ int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd,

wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms));

- return __watchdog_ping(wdd);
+ if (watchdog_hw_running(wdd) && handle_boot_enabled)
+ return __watchdog_ping(wdd);
+ return 0;