Re: [PATCH] watchdog: Add a sysctl to disable soft lockup detector

From: Andrew Morton
Date: Tue Dec 03 2013 - 17:27:59 EST


On Tue, 3 Dec 2013 13:54:34 -0800 Ben Zhang <benzh@xxxxxxxxxxxx> wrote:

> This provides usermode a way to disable only the soft
> lockup detector while keeping the hard lockup detector
> running.

Please update the changelog to describe the current behavior.

Please also describe why you think that behavior should be changed.
ie: what's the reason for this patch.

Please update Documentation/ for this feature. Probably that's
kernel-parameters.txt for the boot option and sysctl/kernel.txt for the
procfs addition.

> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -270,6 +270,7 @@ extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
> void __user *buffer,
> size_t *lenp, loff_t *ppos);
> extern unsigned int softlockup_panic;
> +extern unsigned int softlockup_detector_enable;

Remove unneeded space while we're in there.

> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -840,6 +840,15 @@ static struct ctl_table kern_table[] = {
> .extra2 = &one,
> },
> {
> + .procname = "softlockup_detector_enable",
> + .data = &softlockup_detector_enable,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec_minmax,
> + .extra1 = &zero,
> + .extra2 = &one,
> + },

And let's describe the full procfs path to this pseudo-file within the
changelog.

> .procname = "nmi_watchdog",
> .data = &watchdog_user_enabled,
> .maxlen = sizeof (int),

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