Since zap_class() removes items from the all_lock_classes list and the
classhash_table, protect all zap_class() calls with the graph lock.

Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Waiman Long <long...@redhat.com>
Cc: Johannes Berg <johan...@sipsolutions.net>
Signed-off-by: Bart Van Assche <bvanass...@acm.org>
---
 kernel/locking/lockdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 346b5a1fd062..e78623819184 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4229,6 +4229,7 @@ void lockdep_reset_lock(struct lockdep_map *lock)
        int j, locked;
 
        raw_local_irq_save(flags);
+       locked = graph_lock();
 
        /*
         * Remove all classes this lock might have:
@@ -4245,7 +4246,6 @@ void lockdep_reset_lock(struct lockdep_map *lock)
         * Debug check: in the end all mapped classes should
         * be gone.
         */
-       locked = graph_lock();
        if (unlikely(lock_class_cache_is_registered(lock))) {
                if (debug_locks_off_graph_unlock()) {
                        /*
-- 
2.20.0.rc1.387.gf8505762e3-goog

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