4.19-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 3c5cdb17c3be76714dfd0d03e384f70579545614 ]
When list->count is 0, the list is deleted by GC. But list->count is never reached 0 because initial count value is 1 and it is increased when node is inserted. So that initial value of list->count should be 0.
Originally GC always finds zero count list through deleting node and decreasing count. However, list may be left empty since node insertion may fail eg. allocaton problem. In order to solve this problem, GC routine also finds zero count list without deleting node.
Fixes: cb2b36f5a97d ("netfilter: nf_conncount: Switch to plain list") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_conncount.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c index cb33709138df..8acae4a3e4c0 100644 --- a/net/netfilter/nf_conncount.c +++ b/net/netfilter/nf_conncount.c @@ -144,8 +144,10 @@ static bool conn_free(struct nf_conncount_list *list, list->count--; conn->dead = true; list_del_rcu(&conn->node); - if (list->count == 0) + if (list->count == 0) { + list->dead = true; free_entry = true; + }
spin_unlock_bh(&list->list_lock); call_rcu(&conn->rcu_head, __conn_free); @@ -248,7 +250,7 @@ void nf_conncount_list_init(struct nf_conncount_list *list) { spin_lock_init(&list->list_lock); INIT_LIST_HEAD(&list->head); - list->count = 1; + list->count = 0; list->dead = false; } EXPORT_SYMBOL_GPL(nf_conncount_list_init); @@ -262,6 +264,7 @@ bool nf_conncount_gc_list(struct net *net, struct nf_conn *found_ct; unsigned int collected = 0; bool free_entry = false; + bool ret = false;
list_for_each_entry_safe(conn, conn_n, &list->head, node) { found = find_or_evict(net, list, conn, &free_entry); @@ -291,7 +294,15 @@ bool nf_conncount_gc_list(struct net *net, if (collected > CONNCOUNT_GC_MAX_NODES) return false; } - return false; + + spin_lock_bh(&list->list_lock); + if (!list->count) { + list->dead = true; + ret = true; + } + spin_unlock_bh(&list->list_lock); + + return ret; } EXPORT_SYMBOL_GPL(nf_conncount_gc_list);
@@ -417,6 +428,7 @@ insert_tree(struct net *net, nf_conncount_list_init(&rbconn->list); list_add(&conn->node, &rbconn->list.head); count = 1; + rbconn->list.count = count;
rb_link_node(&rbconn->node, parent, rbnode); rb_insert_color(&rbconn->node, root);