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

If we failed to assign proto idx, we free the twsk_slab_name but forget to
free the twsk_slab. Add a helper function tw_prot_cleanup() to free these
together and also use this helper function in proto_unregister().

Fixes: b45ce32135d1 ("sock: fix potential memory leak in proto_register()")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 net/core/sock.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 49cd5ffe673e..c9083ad44ea1 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c

@@ -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);