Re: [PATCH] net: Fix potential memory leak in proto_register()

From: Cong Wang <redacted>
Date: Tue, 11 Aug 2020 16:02:51 -0700

quoted

@@ -3406,6 +3406,16 @@ static void sock_inuse_add(struct net *net, int val)
 }
 #endif

+static void tw_prot_cleanup(struct timewait_sock_ops *twsk_prot)
+{
+       if (!twsk_prot)
+               return;
+       kfree(twsk_prot->twsk_slab_name);
+       twsk_prot->twsk_slab_name = NULL;
+       kmem_cache_destroy(twsk_prot->twsk_slab);

Hmm, are you sure you can free the kmem cache name before
kmem_cache_destroy()? To me, it seems kmem_cache_destroy()
frees the name via slab_kmem_cache_release() via kfree_const().
With your patch, we have a double-free on the name?

Or am I missing anything?

Yep, there is a double free here.

Please fix this.