2021-08-01 07:58:29

by Jan Kiszka

Subject: [PATCH v2] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate

From: Jan Kiszka <[email protected]>

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 <[email protected]>
---

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;
}
EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive);

--
2.31.1

2021-08-01 17:39:56

by Guenter Roeck

Subject: Re: [PATCH v2] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate

On 8/1/21 12:56 AM, Jan Kiszka wrote:
> From: Jan Kiszka <[email protected]>
>
> 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 <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

> ---
>
> 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;
> }
> EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive);
>
> --
> 2.31.1
>