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From: Jan Kiszka <>
To: Guenter Roeck <>,
	Wim Van Sebroeck <>,
Cc: Linux Kernel Mailing List <>
Subject: [PATCH v2] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate
Date: Sun, 1 Aug 2021 09:56:25 +0200	[thread overview]
Message-ID: <> (raw)

From: Jan Kiszka <>

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 <>

Changes to v1 ("watchdog: Respect handle_boot_enabled when setting last last_hw_keepalive"):
 - add watchdog_hw_running test
 - improve commit log

 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 3bab32485273..6c73160386b9 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -1172,7 +1172,10 @@ 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;


             reply	other threads:[~2021-08-01  7:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-01  7:56 Jan Kiszka [this message]
2021-08-01 17:37 ` Guenter Roeck

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