linux-kernel - [PATCH 5.10 070/122] watchdog: Start watchdog in watchdog_set_last_hw

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Date:   Mon, 20 Sep 2021 18:44:02 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jan Kiszka <jan.kiszka@...mens.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 070/122] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate

From: Jan Kiszka <jan.kiszka@...mens.com>

[ 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@...mens.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
Link: https://lore.kernel.org/r/93d56386-6e37-060b-55ce-84de8cde535f@web.de
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@...ux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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;
 }
 EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive);
 
-- 
2.30.2