2 files changed, 7 insertions, 28 deletions

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 1c185d9dd468..af000956286c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -485,21 +485,6 @@ static void watchdog(unsigned int cpu)
         __this_cpu_write(soft_lockup_hrtimer_cnt,
                          __this_cpu_read(hrtimer_interrupts));
         __touch_watchdog();
-
-        /*
-         * watchdog_nmi_enable() clears the NMI_WATCHDOG_ENABLED bit in the
-         * failure path. Check for failures that can occur asynchronously -
-         * for example, when CPUs are on-lined - and shut down the hardware
-         * perf event on each CPU accordingly.
-         *
-         * The only non-obvious place this bit can be cleared is through
-         * watchdog_nmi_enable(), so a pr_info() is placed there.  Placing a
-         * pr_info here would be too noisy as it would result in a message
-         * every few seconds if the hardlockup was disabled but the softlockup
-         * enabled.
-         */
-        if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
-                watchdog_nmi_disable(cpu);
 }
 
 static struct smp_hotplug_thread watchdog_threads = {
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index c9586ebc2e98..7b602714ea53 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -23,6 +23,7 @@ static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
 
 static unsigned long hardlockup_allcpu_dumped;
+static bool hardlockup_detector_disabled;
 
 void arch_touch_nmi_watchdog(void)
 {
@@ -178,6 +179,10 @@ int watchdog_nmi_enable(unsigned int cpu)
         if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
                 goto out;
 
+        /* A failure disabled the hardlockup detector permanently */
+        if (hardlockup_detector_disabled)
+                return -ENODEV;
+
         /* is it already setup and enabled? */
         if (event && event->state > PERF_EVENT_STATE_OFF)
                 goto out;
@@ -206,18 +211,6 @@ int watchdog_nmi_enable(unsigned int cpu)
                 goto out_save;
         }
 
-        /*
-         * Disable the hard lockup detector if _any_ CPU fails to set up
-         * set up the hardware perf event. The watchdog() function checks
-         * the NMI_WATCHDOG_ENABLED bit periodically.
-         *
-         * The barriers are for syncing up watchdog_enabled across all the
-         * cpus, as clear_bit() does not use barriers.
-         */
-        smp_mb__before_atomic();
-        clear_bit(NMI_WATCHDOG_ENABLED_BIT, &watchdog_enabled);
-        smp_mb__after_atomic();
-
         /* skip displaying the same error again */
         if (!firstcpu && (PTR_ERR(event) == firstcpu_err))
                 return PTR_ERR(event);
@@ -232,7 +225,8 @@ int watchdog_nmi_enable(unsigned int cpu)
                 pr_err("disabled (cpu%i): unable to create perf event: %ld\n",
                         cpu, PTR_ERR(event));
 
-        pr_info("Shutting down hard lockup detector on all cpus\n");
+        pr_info("Disabling hard lockup detector permanently\n");
+        hardlockup_detector_disabled = true;
 
         return PTR_ERR(event);