codetag: debug: skip objext checking when it's for objext itself

objext objects are created with __GFP_NO_OBJ_EXT flag and therefore have
no corresponding objext themselves (otherwise we would get an infinite
recursion). When freeing these objects their codetag will be empty and
when CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled this will lead to false
warnings. Introduce CODETAG_EMPTY special codetag value to mark
allocations which intentionally lack codetag to avoid these warnings.
Set objext codetags to CODETAG_EMPTY before freeing to indicate that
the codetag is expected to be empty.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 21b0b9e9cd9e..d5f75d04ced2 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -242,6 +242,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 		 * assign slabobj_exts in parallel. In this case the existing
 		 * objcg vector should be reused.
 		 */
+		mark_objexts_empty(vec);
 		kfree(vec);
 		return 0;
 	}