linux-kernel - [tip:core/urgent] watchdog/core: Provide interface to stop from poweroff()

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Message-ID: <tip-6554fd8cf06db86f861bb24d7487b2873ca444c4@git.kernel.org>
Date:   Thu, 14 Sep 2017 03:40:46 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     npiggin@...il.com, torvalds@...ux-foundation.org,
        dzickus@...hat.com, akpm@...ux-foundation.org,
        bigeasy@...utronix.de, peterz@...radead.org, uobergfe@...hat.com,
        deller@....de, linux-kernel@...r.kernel.org, bp@...en8.de,
        hpa@...or.com, tglx@...utronix.de, cmetcalf@...lanox.com,
        mingo@...nel.org
Subject: [tip:core/urgent] watchdog/core: Provide interface to stop from
 poweroff()

Commit-ID:  6554fd8cf06db86f861bb24d7487b2873ca444c4
Gitweb:     http://git.kernel.org/tip/6554fd8cf06db86f861bb24d7487b2873ca444c4
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 12 Sep 2017 21:36:57 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 14 Sep 2017 11:41:03 +0200

watchdog/core: Provide interface to stop from poweroff()

PARISC has a a busy looping power off routine. If the watchdog is enabled
the watchdog timer will still fire, but the thread is not running, which
causes the softlockup watchdog to trigger.

Provide a interface which allows to turn the watchdog off.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Don Zickus <dzickus@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Chris Metcalf <cmetcalf@...lanox.com>
Cc: Helge Deller <deller@....de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Sebastian Siewior <bigeasy@...utronix.de>
Cc: Ulrich Obergfell <uobergfe@...hat.com>
Cc: linux-parisc@...r.kernel.org
Link: http://lkml.kernel.org/r/20170912194146.327343752@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 include/linux/nmi.h |  6 +++---
 kernel/watchdog.c   | 14 +++++++++++++-
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index b24d4a5..85bb268b 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -12,10 +12,10 @@
 
 #ifdef CONFIG_LOCKUP_DETECTOR
 void lockup_detector_init(void);
+void lockup_detector_soft_poweroff(void);
 #else
-static inline void lockup_detector_init(void)
-{
-}
+static inline void lockup_detector_init(void) { }
+static inline void lockup_detector_soft_poweroff(void) { }
 #endif
 
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index f5d5202..f23e373 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -333,7 +333,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 	int duration;
 	int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
 
-	if (atomic_read(&watchdog_park_in_progress) != 0)
+	if (!watchdog_enabled ||
+	    atomic_read(&watchdog_park_in_progress) != 0)
 		return HRTIMER_NORESTART;
 
 	/* kick the hardlockup detector */
@@ -660,6 +661,17 @@ static void set_sample_period(void)
 }
 #endif /* SOFTLOCKUP */
 
+/**
+ * lockup_detector_soft_poweroff - Interface to stop lockup detector(s)
+ *
+ * Special interface for parisc. It prevents lockup detector warnings from
+ * the default pm_poweroff() function which busy loops forever.
+ */
+void lockup_detector_soft_poweroff(void)
+{
+	watchdog_enabled = 0;
+}
+
 /*
  * Suspend the hard and soft lockup detector by parking the watchdog threads.
  */