12 files changed, 129 insertions, 104 deletions

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index bb2e0f0975a..64d5ad0b8ad 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 2e03b6d796d..e76d715e434 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 63f81c44846..272995d2029 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 c20943eabb4..02e16d20730 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 47151c8495a..3cd51e579ab 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 2af83825634..3be35f3a001 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
+        help
+          This option provides tracing for the TREE_RCU implementation,
+          permitting Makefile to trivially select kernel/rcutree_trace.c.
+
+config PREEMPT_RCU_TRACE
+        def_bool RCU_TRACE && PREEMPT_RCU
+        select DEBUG_FS
+        help
+          This option provides tracing for the PREEMPT_RCU implementation,
+          permitting Makefile to trivially select kernel/rcupreempt_trace.c.
+
+endmenu # "RCU Subsystem"
+
 config IKCONFIG
         tristate "Kernel .config support"
         ---help---
@@ -972,90 +1064,3 @@ source "block/Kconfig"
 config PREEMPT_NOTIFIERS
         bool
 
-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
-        help
-          This option provides tracing for the TREE_RCU implementation,
-          permitting Makefile to trivially select kernel/rcutree_trace.c.
-
-config PREEMPT_RCU_TRACE
-        def_bool RCU_TRACE && PREEMPT_RCU
-        select DEBUG_FS
-        help
-          This option provides tracing for the PREEMPT_RCU implementation,
-          permitting Makefile to trivially select kernel/rcupreempt_trace.c.
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index 490934fc7ac..bd5a9003497 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -716,7 +716,7 @@ void rcu_check_callbacks(int cpu, int user)
         raise_rcu_softirq();
 }
 
-static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
+static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
                                                 struct rcu_data *rdp)
 {
         unsigned long flags;
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index f2d8638e6c6..b2fd602a6f6 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1314,7 +1314,7 @@ int rcu_needs_cpu(int cpu)
  * access due to the fact that this CPU cannot possibly have any RCU
  * callbacks in flight yet.
  */
-static void
+static void __cpuinit
 rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
 {
         unsigned long flags;
diff --git a/kernel/relay.c b/kernel/relay.c
index 09ac2008f77..9d79b7854fa 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -663,8 +663,10 @@ int relay_late_setup_files(struct rchan *chan,
 
         mutex_lock(&relay_channels_mutex);
         /* Is chan already set up? */
-        if (unlikely(chan->has_base_filename))
+        if (unlikely(chan->has_base_filename)) {
+                mutex_unlock(&relay_channels_mutex);
                 return -EEXIST;
+        }
         chan->has_base_filename = 1;
         chan->parent = parent;
         curr_cpu = get_cpu();
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index d9188c66278..85d5a245510 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -16,6 +16,7 @@
 #include <linux/lockdep.h>
 #include <linux/notifier.h>
 #include <linux/module.h>
+#include <linux/sysctl.h>
 
 #include <asm/irq_regs.h>
 
@@ -88,6 +89,14 @@ void touch_all_softlockup_watchdogs(void)
 }
 EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
 
+int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
+                             struct file *filp, void __user *buffer,
+                             size_t *lenp, loff_t *ppos)
+{
+        touch_all_softlockup_watchdogs();
+        return proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+}
+
 /*
  * This callback runs from the timer interrupt, and checks
  * whether the watchdog thread has hung or not:
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 368d1638ee7..790f9d78566 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -809,7 +809,7 @@ static struct ctl_table kern_table[] = {
                 .data           = &softlockup_thresh,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec_minmax,
+                .proc_handler   = &proc_dosoftlockup_thresh,
                 .strategy       = &sysctl_intvec,
                 .extra1         = &neg_one,
                 .extra2         = &sixty,
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d30561dda90..29044f50026 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -642,19 +642,6 @@ config RCU_TORTURE_TEST_RUNNABLE
 
 config RCU_CPU_STALL_DETECTOR
         bool "Check for stalled CPUs delaying RCU grace periods"
-        depends on CLASSIC_RCU
-        default n
-        help
-          This option causes RCU to printk information on which
-          CPUs are delaying the current grace period, but only when
-          the grace period extends for excessive time periods.
-
-          Say Y if you want RCU to perform such checks.
-
-          Say N if you are unsure.
-
-config RCU_CPU_STALL_DETECTOR
-        bool "Check for stalled CPUs delaying RCU grace periods"
         depends on CLASSIC_RCU || TREE_RCU
         default n
         help