[PATCH RFC 01/12] mm/slab: skip kfence objects in allocation profiling

["Vlastimil Babka (SUSE)" <vbabka@kernel.org>]

struct kfence_metadata only has obj_exts with CONFIG_MEMCG. If it's
enabled, it does also work for allocation profiling, but there's little
value recording tags for KFENCE objects. Furthermore it would complicate
the upcoming changes, so just skip them in the slab hooks.

Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
---
 mm/slub.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index 0337e60db5ac..a4be70d080fb 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2352,6 +2352,9 @@ __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags,
 	if (alloc_flags & SLAB_ALLOC_NO_RECURSE)
 		return;
 
+	if (is_kfence_address(object))
+		return;
+
 	slab = virt_to_slab(object);
 	obj_exts = prepare_slab_obj_exts_hook(s, slab, flags, alloc_flags, object);
 	/*
@@ -2399,6 +2402,9 @@ __alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p
 	for (i = 0; i < objects; i++) {
 		unsigned int off = obj_to_index(s, slab, p[i]);
 
+		if (is_kfence_address(p[i]))
+			continue;
+
 		alloc_tag_sub(&slab_obj_ext(slab, obj_exts, off)->ref, s->size);
 	}
 	put_slab_obj_exts(obj_exts);

-- 
2.55.0