Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fix from Ingo Molnar:
 "Fixes a crash when accessing /proc/lockdep"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Zap lock classes even with lock debugging disabled

1 files changed, 12 insertions, 17 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 34cdcbedda49..e16766ff184b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4689,8 +4689,8 @@ static void free_zapped_rcu(struct rcu_head *ch)
                 return;
 
         raw_local_irq_save(flags);
-        if (!graph_lock())
-                goto out_irq;
+        arch_spin_lock(&lockdep_lock);
+        current->lockdep_recursion = 1;
 
         /* closed head */
         pf = delayed_free.pf + (delayed_free.index ^ 1);
@@ -4702,8 +4702,8 @@ static void free_zapped_rcu(struct rcu_head *ch)
          */
         call_rcu_zapped(delayed_free.pf + delayed_free.index);
 
-        graph_unlock();
-out_irq:
+        current->lockdep_recursion = 0;
+        arch_spin_unlock(&lockdep_lock);
         raw_local_irq_restore(flags);
 }
 
@@ -4744,21 +4744,17 @@ static void lockdep_free_key_range_reg(void *start, unsigned long size)
 {
         struct pending_free *pf;
         unsigned long flags;
-        int locked;
 
         init_data_structures_once();
 
         raw_local_irq_save(flags);
-        locked = graph_lock();
-        if (!locked)
-                goto out_irq;
-
+        arch_spin_lock(&lockdep_lock);
+        current->lockdep_recursion = 1;
         pf = get_pending_free();
         __lockdep_free_key_range(pf, start, size);
         call_rcu_zapped(pf);
-
-        graph_unlock();
-out_irq:
+        current->lockdep_recursion = 0;
+        arch_spin_unlock(&lockdep_lock);
         raw_local_irq_restore(flags);
 
         /*
@@ -4911,9 +4907,8 @@ void lockdep_unregister_key(struct lock_class_key *key)
                 return;
 
         raw_local_irq_save(flags);
-        if (!graph_lock())
-                goto out_irq;
-
+        arch_spin_lock(&lockdep_lock);
+        current->lockdep_recursion = 1;
         pf = get_pending_free();
         hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
                 if (k == key) {
@@ -4925,8 +4920,8 @@ void lockdep_unregister_key(struct lock_class_key *key)
         WARN_ON_ONCE(!found);
         __lockdep_free_key_range(pf, key, 1);
         call_rcu_zapped(pf);
-        graph_unlock();
-out_irq:
+        current->lockdep_recursion = 0;
+        arch_spin_unlock(&lockdep_lock);
         raw_local_irq_restore(flags);
 
         /* Wait until is_dynamic_key() has finished accessing k->hash_entry. */