debugobjects: avoid recursive calls with kmemleak

CONFIG_DEBUG_OBJECTS_RCU_HEAD does not play well with kmemleak due to
recursive calls.

fill_pool
  kmemleak_ignore
    make_black_object
      put_object
        __call_rcu (kernel/rcu/tree.c)
          debug_rcu_head_queue
            debug_object_activate
              debug_object_init
                fill_pool
                  kmemleak_ignore
                    make_black_object
                      ...

So add SLAB_NOLEAKTRACE to kmem_cache_create() to not register newly
allocated debug objects at all.

Link: http://lkml.kernel.org/r/20181126165343.2339-1-cai@gmx.us
Signed-off-by: Qian Cai <cai@gmx.us>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 70935ed91125..14afeeb7d6ef 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -135,7 +135,6 @@ static void fill_pool(void)
                 if (!new)
                         return;
 
-                kmemleak_ignore(new);
                 raw_spin_lock_irqsave(&pool_lock, flags);
                 hlist_add_head(&new->node, &obj_pool);
                 debug_objects_allocated++;
@@ -1128,7 +1127,6 @@ static int __init debug_objects_replace_static_objects(void)
                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
                 if (!obj)
                         goto free;
-                kmemleak_ignore(obj);
                 hlist_add_head(&obj->node, &objects);
         }
 
@@ -1184,7 +1182,8 @@ void __init debug_objects_mem_init(void)
 
         obj_cache = kmem_cache_create("debug_objects_cache",
                                       sizeof (struct debug_obj), 0,
-                                      SLAB_DEBUG_OBJECTS, NULL);
+                                      SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
+                                      NULL);
 
         if (!obj_cache || debug_objects_replace_static_objects()) {
                 debug_objects_enabled = 0;