Commit 11295055 authored Nov 01, 2018 by Laurence Oberman Committed by Thomas Gleixner Nov 01, 2018

watchdog/core: Add watchdog_thresh command line parameter



The hard and soft lockup detector threshold has a default value of 10
seconds which can only be changed via sysctl.

During early boot lockup detection can trigger when noisy debugging emits
a large amount of messages to the console, but there is no way to set a
larger threshold on the kernel command line. The detector can only be
completely disabled.

Add a new watchdog_thresh= command line parameter to allow boot time
control over the threshold. It works in the same way as the sysctl and
affects both the soft and the hard lockup detectors.

Signed-off-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: rdunlap@infradead.org
Cc: prarit@redhat.com
Link: https://lkml.kernel.org/r/1541079018-13953-1-git-send-email-loberman@redhat.com

parent 5b744981

Documentation/admin-guide/kernel-parameters.txt

+8 −0

Original line number	Diff line number	Diff line
		@@ -4957,6 +4957,14 @@
		or other driver-specific files in the
		Documentation/watchdog/ directory.

		watchdog_thresh=
		[KNL]
		Set the hard lockup detector stall duration
		threshold in seconds. The soft lockup detector
		threshold is set to twice the value. A value of 0
		disables both lockup detectors. Default is 10
		seconds.

		workqueue.watchdog_thresh=
		If CONFIG_WQ_WATCHDOG is configured, workqueue can
		warn stall conditions and dump internal state to

kernel/watchdog.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -199,6 +199,13 @@ static int __init nosoftlockup_setup(char *str)
		}
		__setup("nosoftlockup", nosoftlockup_setup);

		static int __init watchdog_thresh_setup(char *str)
		{
		get_option(&str, &watchdog_thresh);
		return 1;
		}
		__setup("watchdog_thresh=", watchdog_thresh_setup);

		#ifdef CONFIG_SMP
		int __read_mostly sysctl_softlockup_all_cpu_backtrace;

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