@@ -83,9 +83,11 @@ static inline void reset_hung_task_detector(void) { }
#if defined(CONFIG_HARDLOCKUP_DETECTOR)
extern void hardlockup_detector_disable(void);
+extern void hardlockup_detector_mark_unavailable(void);
extern unsigned int hardlockup_panic;
#else
static inline void hardlockup_detector_disable(void) {}
+static inline void hardlockup_detector_mark_unavailable(void) {}
#endif
#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
@@ -47,6 +47,8 @@ static int __read_mostly nmi_watchdog_available;
struct cpumask watchdog_cpumask __read_mostly;
unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
+static void __lockup_detector_reconfigure(void);
+
#ifdef CONFIG_HARDLOCKUP_DETECTOR
# ifdef CONFIG_SMP
@@ -85,6 +87,24 @@ static int __init hardlockup_panic_setup(char *str)
}
__setup("nmi_watchdog=", hardlockup_panic_setup);
+/**
+ * hardlockup_detector_mark_unavailable - Mark the NMI watchdog as unavailable
+ *
+ * Indicate that the hardlockup detector has become unavailable. This may
+ * happen if the hardware resources that the detector uses have become
+ * unreliable.
+ */
+void hardlockup_detector_mark_unavailable(void)
+{
+ mutex_lock(&watchdog_mutex);
+
+ /* These variables can be updated without stopping the detector. */
+ nmi_watchdog_user_enabled = 0;
+ nmi_watchdog_available = false;
+
+ __lockup_detector_reconfigure();
+ mutex_unlock(&watchdog_mutex);
+}
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
/*
The NMI watchdog may become unreliable during runtime. This is the case in x86 if, for instance, the HPET-based hardlockup detector is in use and the TSC counter becomes unstable. Introduce a new interface to mark the hardlockup detector as unavailable in such cases. When doing this, update the state of /proc/sys/kernel/ nmi_watchdog to keep it consistent. Cc: Andi Kleen <ak@linux.intel.com> Cc: Stephane Eranian <eranian@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: iommu@lists.linux-foundation.org Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> --- Changes since v6: * Introduced this patch Changes since v5: * N/A Changes since v4 * N/A Changes since v3 * N/A Changes since v2: * N/A Changes since v1: * N/A --- include/linux/nmi.h | 2 ++ kernel/watchdog.c | 20 ++++++++++++++++++++ 2 files changed, 22 insertions(+)