SLAB: Record actual last user of freed objects.

Currently, when using CONFIG_DEBUG_SLAB, we put in kfree() or
kmem_cache_free() as the last user of free objects, which is not
very useful, so change it to the caller of those functions instead.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/mm/slab.c b/mm/slab.c
index bcfa4987c8ae..d96e223de775 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3604,13 +3604,14 @@ free_done:
  * Release an obj back to its cache. If the obj has a constructed state, it must
  * be in this state _before_ it is released.  Called with disabled ints.
  */
-static inline void __cache_free(struct kmem_cache *cachep, void *objp)
+static inline void __cache_free(struct kmem_cache *cachep, void *objp,
+    void *caller)
 {
         struct array_cache *ac = cpu_cache_get(cachep);
 
         check_irq_off();
         kmemleak_free_recursive(objp, cachep->flags);
-        objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
+        objp = cache_free_debugcheck(cachep, objp, caller);
 
         kmemcheck_slab_free(cachep, objp, obj_size(cachep));
 
@@ -3801,7 +3802,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
         debug_check_no_locks_freed(objp, obj_size(cachep));
         if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
                 debug_check_no_obj_freed(objp, obj_size(cachep));
-        __cache_free(cachep, objp);
+        __cache_free(cachep, objp, __builtin_return_address(0));
         local_irq_restore(flags);
 
         trace_kmem_cache_free(_RET_IP_, objp);
@@ -3831,7 +3832,7 @@ void kfree(const void *objp)
         c = virt_to_cache(objp);
         debug_check_no_locks_freed(objp, obj_size(c));
         debug_check_no_obj_freed(objp, obj_size(c));
-        __cache_free(c, (void *)objp);
+        __cache_free(c, (void *)objp, __builtin_return_address(0));
         local_irq_restore(flags);
 }
 EXPORT_SYMBOL(kfree);