slub: Bug on free of non-slab objects

Before commit d0fe47c ("slub: add back check for free nonslab
objects"), freeing a non-slab object used to trigger a BUG if
CONFIG_DEBUG_VM was enabled. Now it only warns, which I think is not
enough for such a memory corruption. Let's restore the previous
behaviour, but tie it to CONFIG_BUG_ON_DATA_CORRUPTION as suggested by
Levente.

After page folios were introduced in v5.17, this patch was adapted to
trigger a bug when the order of the folio is zero instead of when the
page is not a compound page, which is not equivalent but respects the
semantics of the conversion to page folios and follows the change made
to the WARN_ON_ONCE beneath.

Suggested-by: Levente Polyak <[email protected]>
Signed-off-by: Thibaut Sautereau <[email protected]>

Author: tsautereau-anssi

mm/slab_common.c

@@ -901,8 +901,12 @@ void free_large_kmalloc(struct folio *folio, void *object)
 {
 	unsigned int order = folio_order(folio);
 
+#ifdef CONFIG_BUG_ON_DATA_CORRUPTION
+	BUG_ON(order == 0);
+#else
 	if (WARN_ON_ONCE(order == 0))
 		pr_warn_once("object pointer: 0x%p\n", object);
+#endif
 
 	kmemleak_free(object);
 	kasan_kfree_large(object);