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:
  locking: Make sparse work with inline spinlocks and rwlocks
  x86/mce: Fix RCU lockdep splats
  rcu: Increase RCU CPU stall timeouts if PROVE_RCU
  ftrace: Replace read_barrier_depends() with rcu_dereference_raw()
  rcu: Suppress RCU lockdep warnings during early boot
  rcu, ftrace: Fix RCU lockdep splat in ftrace_perf_buf_prepare()
  rcu: Suppress __mpol_dup() false positive from RCU lockdep
  rcu: Make rcu_read_lock_sched_held() handle !PREEMPT
  rcu: Add control variables to lockdep_rcu_dereference() diagnostics
  rcu, cgroup: Relax the check in task_subsys_state() as early boot is now handled by lockdep-RCU
  rcu: Use wrapper function instead of exporting tasklist_lock
  sched, rcu: Fix rcu_dereference() for RCU-lockdep
  rcu: Make task_subsys_state() RCU-lockdep checks handle boot-time use
  rcu: Fix holdoff for accelerated GPs for last non-dynticked CPU
  x86/gart: Unexport gart_iommu_aperture

Fix trivial conflicts in kernel/trace/ftrace.c

18 files changed, 120 insertions, 55 deletions

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index f147a95fd84a..3704997e8b25 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -31,7 +31,6 @@
 #include <asm/x86_init.h>
 
 int gart_iommu_aperture;
-EXPORT_SYMBOL_GPL(gart_iommu_aperture);
 int gart_iommu_aperture_disabled __initdata;
 int gart_iommu_aperture_allowed __initdata;
 
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 28cba46bf32c..bd58de4d7a29 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -46,6 +46,11 @@
 
 #include "mce-internal.h"
 
+#define rcu_dereference_check_mce(p) \
+        rcu_dereference_check((p), \
+                              rcu_read_lock_sched_held() || \
+                              lockdep_is_held(&mce_read_mutex))
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/mce.h>
 
@@ -158,7 +163,7 @@ void mce_log(struct mce *mce)
         mce->finished = 0;
         wmb();
         for (;;) {
-                entry = rcu_dereference(mcelog.next);
+                entry = rcu_dereference_check_mce(mcelog.next);
                 for (;;) {
                         /*
                          * When the buffer fills up discard new entries.
@@ -1500,7 +1505,7 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
                 return -ENOMEM;
 
         mutex_lock(&mce_read_mutex);
-        next = rcu_dereference(mcelog.next);
+        next = rcu_dereference_check_mce(mcelog.next);
 
         /* Only supports full reads right now */
         if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
@@ -1565,7 +1570,7 @@ timeout:
 static unsigned int mce_poll(struct file *file, poll_table *wait)
 {
         poll_wait(file, &mce_wait, wait);
-        if (rcu_dereference(mcelog.next))
+        if (rcu_dereference_check_mce(mcelog.next))
                 return POLLIN | POLLRDNORM;
         return 0;
 }
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 4db09f89b637..52507c3e1387 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -280,7 +280,7 @@ static inline void put_cred(const struct cred *_cred)
  * task or by holding tasklist_lock to prevent it from being unlinked.
  */
 #define __task_cred(task) \
-        ((const struct cred *)(rcu_dereference_check((task)->real_cred, rcu_read_lock_held() || lockdep_is_held(&tasklist_lock))))
+        ((const struct cred *)(rcu_dereference_check((task)->real_cred, rcu_read_lock_held() || lockdep_tasklist_lock_is_held())))
 
 /**
  * get_task_cred - Get another task's objective credentials
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a005cac5e302..3024050c82a1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -101,6 +101,11 @@ extern struct lockdep_map rcu_sched_lock_map;
 # define rcu_read_release_sched() \
                 lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
 
+static inline int debug_lockdep_rcu_enabled(void)
+{
+        return likely(rcu_scheduler_active && debug_locks);
+}
+
 /**
  * rcu_read_lock_held - might we be in RCU read-side critical section?
  *
@@ -108,12 +113,14 @@ extern struct lockdep_map rcu_sched_lock_map;
  * an RCU read-side critical section.  In absence of CONFIG_PROVE_LOCKING,
  * this assumes we are in an RCU read-side critical section unless it can
  * prove otherwise.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
  */
 static inline int rcu_read_lock_held(void)
 {
-        if (debug_locks)
-                return lock_is_held(&rcu_lock_map);
-        return 1;
+        if (!debug_lockdep_rcu_enabled())
+                return 1;
+        return lock_is_held(&rcu_lock_map);
 }
 
 /**
@@ -123,12 +130,14 @@ static inline int rcu_read_lock_held(void)
  * an RCU-bh read-side critical section.  In absence of CONFIG_PROVE_LOCKING,
  * this assumes we are in an RCU-bh read-side critical section unless it can
  * prove otherwise.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
  */
 static inline int rcu_read_lock_bh_held(void)
 {
-        if (debug_locks)
-                return lock_is_held(&rcu_bh_lock_map);
-        return 1;
+        if (!debug_lockdep_rcu_enabled())
+                return 1;
+        return lock_is_held(&rcu_bh_lock_map);
 }
 
 /**
@@ -139,15 +148,26 @@ static inline int rcu_read_lock_bh_held(void)
  * this assumes we are in an RCU-sched read-side critical section unless it
  * can prove otherwise.  Note that disabling of preemption (including
  * disabling irqs) counts as an RCU-sched read-side critical section.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
  */
+#ifdef CONFIG_PREEMPT
 static inline int rcu_read_lock_sched_held(void)
 {
         int lockdep_opinion = 0;
 
+        if (!debug_lockdep_rcu_enabled())
+                return 1;
         if (debug_locks)
                 lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
-        return lockdep_opinion || preempt_count() != 0 || !rcu_scheduler_active;
+        return lockdep_opinion || preempt_count() != 0;
+}
+#else /* #ifdef CONFIG_PREEMPT */
+static inline int rcu_read_lock_sched_held(void)