Show random secret in /sys/kernel/slab/*/random

slub-sysfs-random.patch

diff --git a/mm/slub.c b/mm/slub.c
index 332d4b459a90..62b300c93ea1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5148,6 +5148,14 @@ static ssize_t usersize_show(struct kmem_cache *s, char *buf)
 }
 SLAB_ATTR_RO(usersize);
 
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+static ssize_t random_show(struct kmem_cache *s, char *buf)
+{
+       return sprintf(buf, "0x%08lx\n", s->random);
+}
+SLAB_ATTR_RO(random);
+#endif
+
 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
 {
        return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
@@ -5517,6 +5525,9 @@ static struct attribute *slab_attrs[] = {
        &failslab_attr.attr,
 #endif
        &usersize_attr.attr,
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+       &random_attr.attr,
+#endif
 
        NULL
 };