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:
  debugobjects: add and use INIT_WORK_ON_STACK
  rcu: remove duplicate CONFIG_RCU_CPU_STALL_DETECTOR
  relay: fix lock imbalance in relay_late_setup_files
  oprofile: fix uninitialized use of struct op_entry
  rcu: move Kconfig menu
  softlock: fix false panic which can occur if softlockup_thresh is reduced
  rcu: add __cpuinit to rcu_init_percpu_data()

12 files changed, 129 insertions, 104 deletions

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index bb2e0f0975ae..64d5ad0b8add 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -633,6 +633,7 @@ static int hpet_cpuhp_notify(struct notifier_block *n,
                 /* FIXME: add schedule_work_on() */
                 schedule_delayed_work_on(cpu, &work.work, 0);
                 wait_for_completion(&work.complete);
+                destroy_timer_on_stack(&work.work.timer);
                 break;
         case CPU_DEAD:
                 if (hdev) {
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 2e03b6d796d3..e76d715e4342 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -393,16 +393,21 @@ oprofile_write_reserve(struct op_entry *entry, struct pt_regs * const regs,
         return;
 
 fail:
+        entry->event = NULL;
         cpu_buf->sample_lost_overflow++;
 }
 
 int oprofile_add_data(struct op_entry *entry, unsigned long val)
 {
+        if (!entry->event)
+                return 0;
         return op_cpu_buffer_add_data(entry, val);
 }
 
 int oprofile_write_commit(struct op_entry *entry)
 {
+        if (!entry->event)
+                return -EINVAL;
         return op_cpu_buffer_write_commit(entry);
 }
 
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 63f81c44846a..272995d20293 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -66,6 +66,13 @@ static inline void op_cpu_buffer_reset(int cpu)
         cpu_buf->last_task = NULL;
 }
 
+/*
+ * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
+ * called only if op_cpu_buffer_write_reserve() did not return NULL or
+ * entry->event != NULL, otherwise entry->size or entry->event will be
+ * used uninitialized.
+ */
+
 struct op_sample
 *op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
 int op_cpu_buffer_write_commit(struct op_entry *entry);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c20943eabb4c..02e16d207304 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -293,6 +293,9 @@ extern void sched_show_task(struct task_struct *p);
 extern void softlockup_tick(void);
 extern void touch_softlockup_watchdog(void);
 extern void touch_all_softlockup_watchdogs(void);
+extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
+                                    struct file *filp, void __user *buffer,
+                                    size_t *lenp, loff_t *ppos);
 extern unsigned int  softlockup_panic;
 extern unsigned long sysctl_hung_task_check_count;
 extern unsigned long sysctl_hung_task_timeout_secs;
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 47151c8495aa..3cd51e579ab1 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -130,6 +130,12 @@ struct execute_work {
                 init_timer_deferrable(&(_work)->timer);         \
         } while (0)
 
+#define INIT_DELAYED_WORK_ON_STACK(_work, _func)                \
+        do {                                                    \
+                INIT_WORK(&(_work)->work, (_func));             \
+                init_timer_on_stack(&(_work)->timer);           \
+        } while (0)
+
 /**
  * work_pending - Find out whether a work item is currently pending
  * @work: The work item in question
diff --git a/init/Kconfig b/init/Kconfig
index 2af83825634e..3be35f3a001b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -238,6 +238,98 @@ config AUDIT_TREE
         def_bool y
         depends on AUDITSYSCALL && INOTIFY
 
+menu "RCU Subsystem"
+
+choice
+        prompt "RCU Implementation"
+        default CLASSIC_RCU
+
+config CLASSIC_RCU
+        bool "Classic RCU"
+        help
+          This option selects the classic RCU implementation that is
+          designed for best read-side performance on non-realtime
+          systems.
+
+          Select this option if you are unsure.
+
+config TREE_RCU
+        bool "Tree-based hierarchical RCU"
+        help
+          This option selects the RCU implementation that is
+          designed for very large SMP system with hundreds or
+          thousands of CPUs.
+
+config PREEMPT_RCU
+        bool "Preemptible RCU"
+        depends on PREEMPT
+        help
+          This option reduces the latency of the kernel by making certain
+          RCU sections preemptible. Normally RCU code is non-preemptible, if
+          this option is selected then read-only RCU sections become
+          preemptible. This helps latency, but may expose bugs due to
+          now-naive assumptions about each RCU read-side critical section
+          remaining on a given CPU through its execution.
+
+endchoice
+
+config RCU_TRACE
+        bool "Enable tracing for RCU"
+        depends on TREE_RCU || PREEMPT_RCU
+        help
+          This option provides tracing in RCU which presents stats
+          in debugfs for debugging RCU implementation.
+
+          Say Y here if you want to enable RCU tracing
+          Say N if you are unsure.
+
+config RCU_FANOUT
+        int "Tree-based hierarchical RCU fanout value"
+        range 2 64 if 64BIT
+        range 2 32 if !64BIT
+        depends on TREE_RCU
+        default 64 if 64BIT
+        default 32 if !64BIT
+        help
+          This option controls the fanout of hierarchical implementations
+          of RCU, allowing RCU to work efficiently on machines with
+          large numbers of CPUs.  This value must be at least the cube
+          root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
+          systems and up to 262,144 for 64-bit systems.
+
+          Select a specific number if testing RCU itself.
+          Take the default if unsure.
+
+config RCU_FANOUT_EXACT
+        bool "Disable tree-based hierarchical RCU auto-balancing"
+        depends on TREE_RCU
+        default n
+        help
+          This option forces use of the exact RCU_FANOUT value specified,
+          regardless of imbalances in the hierarchy.  This is useful for
+          testing RCU itself, and might one day be useful on systems with
+          strong NUMA behavior.
+
+          Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
+
+          Say N if unsure.
+
+config TREE_RCU_TRACE
+        def_bool RCU_TRACE && TREE_RCU
+        select DEBUG_FS
+        h