linux-kernel - [PATCH 2/2] watchdog: don't enable watchdog if user disabled it

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Date:   Sun,  7 Aug 2022 23:18:44 +0800
From:   Puyou Lu <puyou.lu@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Puyou Lu <puyou.lu@...il.com>, Petr Mladek <pmladek@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Xiaoming Ni <nixiaoming@...wei.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Frederic Weisbecker <frederic@...nel.org>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] watchdog: don't enable watchdog if user disabled it

Take a check of watchdog_enabled before reconfigure/enable watchdog.

Signed-off-by: Puyou Lu <puyou.lu@...il.com>
---
 kernel/watchdog.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index bed1fe7ecaea..791765c9bece 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -454,6 +454,9 @@ static void watchdog_enable(unsigned int cpu)
 
 	WARN_ON_ONCE(cpu != smp_processor_id());
 
+	if (!watchdog_enabled)
+		return;
+
 	init_completion(done);
 	complete(done);
 
@@ -546,6 +549,10 @@ static void __lockup_detector_reconfigure(void)
 
 	set_sample_period();
 	lockup_detector_update_enable();
+
+	if (!watchdog_enabled)
+		return;
+
 	if (watchdog_enabled & SOFT_WATCHDOG_ENABLED)
 		softlockup_start_all();
 
@@ -591,6 +598,10 @@ static void __lockup_detector_reconfigure(void)
 	cpus_read_lock();
 	watchdog_nmi_stop();
 	lockup_detector_update_enable();
+
+	if (!watchdog_enabled)
+		return;
+
 	watchdog_nmi_start();
 	cpus_read_unlock();
 }
-- 
2.17.1