Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Remove excessive early_res debug output
  softlockup: Stop spurious softlockup messages due to overflow
  rcu: Fix local_irq_disable() CONFIG_PROVE_RCU=y false positives
  rcu: Fix tracepoints & lockdep false positive
  rcu: Make rcu_read_lock_bh_held() allow for disabled BH

2 files changed, 25 insertions, 2 deletions

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f1125c1a6321..63fe25433980 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -45,6 +45,7 @@
 #include <linux/mutex.h>
 #include <linux/module.h>
 #include <linux/kernel_stat.h>
+#include <linux/hardirq.h>
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 static struct lock_class_key rcu_lock_key;
@@ -66,6 +67,28 @@ EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
 int rcu_scheduler_active __read_mostly;
 EXPORT_SYMBOL_GPL(rcu_scheduler_active);
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+/**
+ * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section?
+ *
+ * Check for bottom half being disabled, which covers both the
+ * CONFIG_PROVE_RCU and not cases.  Note that if someone uses
+ * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled)
+ * will show the situation.
+ *
+ * Check debug_lockdep_rcu_enabled() to prevent false positives during boot.
+ */
+int rcu_read_lock_bh_held(void)
+{
+        if (!debug_lockdep_rcu_enabled())
+                return 1;
+        return in_softirq();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
 /*
  * This function is invoked towards the end of the scheduler's initialization
  * process.  Before this is called, the idle task might contain
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 0d4c7898ab80..4b493f67dcb5 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -155,11 +155,11 @@ void softlockup_tick(void)
          * Wake up the high-prio watchdog task twice per
          * threshold timespan.
          */
-        if (now > touch_ts + softlockup_thresh/2)
+        if (time_after(now - softlockup_thresh/2, touch_ts))
                 wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
 
         /* Warn about unreasonable delays: */
-        if (now <= (touch_ts + softlockup_thresh))
+        if (time_before_eq(now - softlockup_thresh, touch_ts))
                 return;
 
         per_cpu(softlockup_print_ts, this_cpu) = touch_ts;