Re: [PATCH 1/5] watchdog: fix error handling in proc_watchdog_thresh()

[Aaron Tomlin]

On Mon 2015-09-28 22:44 +0200, Ulrich Obergfell wrote:
> Restore the previous value of watchdog_thresh _and_ sample_period
> if proc_watchdog_update() returns an error. The variables must be
> consistent to avoid false positives of the lockup detectors.
> 
> Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
> ---
>  kernel/watchdog.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 64ed1c3..cd9a504 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -914,13 +914,14 @@ int proc_watchdog_thresh(struct ctl_table *table, int write,
>  		goto out;
>  
>  	/*
> -	 * Update the sample period.
> -	 * Restore 'watchdog_thresh' on failure.
> +	 * Update the sample period. Restore on failure.
>  	 */
>  	set_sample_period();
>  	err = proc_watchdog_update();
> -	if (err)
> +	if (err) {
>  		watchdog_thresh = old;
> +		set_sample_period();
> +	}
>  out:
>  	mutex_unlock(&watchdog_proc_mutex);
>  	return err;

Reviewed-by: Aaron Tomlin <atomlin@xxxxxxxxxx>

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