watchdog: Mark watchdog_hrtimer to expire in hard interrupt context

The watchdog hrtimer must expire in hard interrupt context even on
PREEMPT_RT=y kernels as otherwise the hard/softlockup detection logic would
not work.

No functional change.

[ tglx: Split out from larger combo patch. Added changelog ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726185753.262895510@linutronix.de

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 7f9e7b9306fe2488622f4b2fc6185419b69d549f..f41334ef097130da12b365e61ae75533775205ad 100644 (file)
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -490,10 +490,10 @@ static void watchdog_enable(unsigned int cpu)
         * Start the timer first to prevent the NMI watchdog triggering
         * before the timer has a chance to fire.
         */
-       hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
        hrtimer->function = watchdog_timer_fn;
        hrtimer_start(hrtimer, ns_to_ktime(sample_period),
-                     HRTIMER_MODE_REL_PINNED);
+                     HRTIMER_MODE_REL_PINNED_HARD);
 
        /* Initialize timestamp */
        __touch_watchdog();