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-rw-r--r--mm/kmemleak.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 8a57e34625fa..c0fd7769d227 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -53,6 +53,11 @@
* modifications to the memory scanning parameters including the scan_thread
* pointer
*
+ * Locks and mutexes should only be acquired/nested in the following order:
+ *
+ * scan_mutex -> object->lock -> other_object->lock (SINGLE_DEPTH_NESTING)
+ * -> kmemleak_lock
+ *
* The kmemleak_object structures have a use_count incremented or decremented
* using the get_object()/put_object() functions. When the use_count becomes
* 0, this count can no longer be incremented and put_object() schedules the
@@ -603,11 +608,13 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
kmemleak_stop("Cannot insert 0x%lx into the object "
"search tree (overlaps existing)\n",
ptr);
+ /*
+ * No need for parent->lock here since "parent" cannot
+ * be freed while the kmemleak_lock is held.
+ */
+ dump_object_info(parent);
kmem_cache_free(object_cache, object);
- object = parent;
- spin_lock(&object->lock);
- dump_object_info(object);
- spin_unlock(&object->lock);
+ object = NULL;
goto out;
}
}