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

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (44 commits)
  rcu: Fix accelerated GPs for last non-dynticked CPU
  rcu: Make non-RCU_PROVE_LOCKING rcu_read_lock_sched_held() understand boot
  rcu: Fix accelerated grace periods for last non-dynticked CPU
  rcu: Export rcu_scheduler_active
  rcu: Make rcu_read_lock_sched_held() take boot time into account
  rcu: Make lockdep_rcu_dereference() message less alarmist
  sched, cgroups: Fix module export
  rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information
  rcu: Fix rcutorture mod_timer argument to delay one jiffy
  rcu: Fix deadlock in TREE_PREEMPT_RCU CPU stall detection
  rcu: Convert to raw_spinlocks
  rcu: Stop overflowing signed integers
  rcu: Use canonical URL for Mathieu's dissertation
  rcu: Accelerate grace period if last non-dynticked CPU
  rcu: Fix citation of Mathieu's dissertation
  rcu: Documentation update for CONFIG_PROVE_RCU
  security: Apply lockdep-based checking to rcu_dereference() uses
  idr: Apply lockdep-based diagnostics to rcu_dereference() uses
  radix-tree: Disable RCU lockdep checking in radix tree
  vfs: Abstract rcu_dereference_check for files-fdtable use
  ...

1 files changed, 18 insertions, 0 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index c62ec14609b9..0c30d0455de1 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3809,3 +3809,21 @@ void lockdep_sys_exit(void)
                 lockdep_print_held_locks(curr);
         }
 }
+
+void lockdep_rcu_dereference(const char *file, const int line)
+{
+        struct task_struct *curr = current;
+
+        if (!debug_locks_off())
+                return;
+        printk("\n===================================================\n");
+        printk(  "[ INFO: suspicious rcu_dereference_check() usage. ]\n");
+        printk(  "---------------------------------------------------\n");
+        printk("%s:%d invoked rcu_dereference_check() without protection!\n",
+                        file, line);
+        printk("\nother info that might help us debug this:\n\n");
+        lockdep_print_held_locks(curr);
+        printk("\nstack backtrace:\n");
+        dump_stack();
+}
+EXPORT_SYMBOL_GPL(lockdep_rcu_dereference);