linux-kernel - Re: [PATCH v2] drivers: watchdog: Add support for panic notifier callback

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Message-ID: <3308b190-b639-4aff-a1f8-3ad9761dd991@roeck-us.net>
Date: Tue, 25 Feb 2025 05:14:05 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: George Cherian <george.cherian@...vell.com>, wim@...ux-watchdog.org,
 corbet@....net
Cc: linux-watchdog@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drivers: watchdog: Add support for panic notifier
 callback

On 2/25/25 01:52, George Cherian wrote:
> Watchdog is not turned off in kernel panic situation.
> In certain systems this might prevent the successful loading
> of kdump kernel. The kdump kernel might hit a watchdog reset
> while it is booting.
> 
> To avoid such scenarios add a panic notifier call back function
> which can stop the watchdog. This provision can be enabled by
> passing watchdog.stop_on_panic=1 via kernel command-line parameter.
> 
> Signed-off-by: George Cherian <george.cherian@...vell.com>
> ---
> Changelog:
> v1 -> v2
> - Remove the per driver flag setting option

You didn't actually remove it.

> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
> index d46d8c8c01f2..8cbebe38b7dd 100644
> --- a/drivers/watchdog/watchdog_core.c
> +++ b/drivers/watchdog/watchdog_core.c
...>
> +/* Use the following function to stop the watchdog on panic */
> +static inline void watchdog_stop_on_panic(struct watchdog_device *wdd)
> +{
> +	set_bit(WDOG_STOP_ON_PANIC, &wdd->status);
> +}

Under what circumstance could or would a _driver_ request this ?
I do not see the use case, sorry.

Guenter