Commit-ID:  6554fd8cf06db86f861bb24d7487b2873ca444c4
Gitweb:     http://git.kernel.org/tip/6554fd8cf06db86f861bb24d7487b2873ca444c4
Author:     Thomas Gleixner <[email protected]>
AuthorDate: Tue, 12 Sep 2017 21:36:57 +0200
Committer:  Ingo Molnar <[email protected]>
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 <[email protected]>
Reviewed-by: Don Zickus <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Siewior <[email protected]>
Cc: Ulrich Obergfell <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 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.
  */

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