From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19529C282C4 for ; Mon, 4 Feb 2019 12:33:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E88D8214DA for ; Mon, 4 Feb 2019 12:33:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730035AbfBDMdv (ORCPT ); Mon, 4 Feb 2019 07:33:51 -0500 Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:57311 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730628AbfBDMds (ORCPT ); Mon, 4 Feb 2019 07:33:48 -0500 Received: from Internal Mail-Server by MTLPINE1 (envelope-from vladbu@mellanox.com) with ESMTPS (AES256-SHA encrypted); 4 Feb 2019 14:33:32 +0200 Received: from reg-r-vrt-018-180.mtr.labs.mlnx. (reg-r-vrt-018-180.mtr.labs.mlnx [10.213.18.180]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x14CXVGO032317; Mon, 4 Feb 2019 14:33:32 +0200 From: Vlad Buslov To: netdev@vger.kernel.org Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Vlad Buslov Subject: [PATCH net-next v3 10/16] net: sched: prevent insertion of new classifiers during chain flush Date: Mon, 4 Feb 2019 14:32:55 +0200 Message-Id: <20190204123301.4223-11-vladbu@mellanox.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20190204123301.4223-1-vladbu@mellanox.com> References: <20190204123301.4223-1-vladbu@mellanox.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Extend tcf_chain with 'flushing' flag. Use the flag to prevent insertion of new classifier instances when chain flushing is in progress in order to prevent resource leak when tcf_proto is created by unlocked users concurrently. Return EAGAIN error from tcf_chain_tp_insert_unique() to restart tc_new_tfilter() and lookup the chain/proto again. Signed-off-by: Vlad Buslov --- include/net/sch_generic.h | 1 + net/sched/cls_api.c | 35 +++++++++++++++++++++++++++++------ 2 files changed, 30 insertions(+), 6 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 083e566fc380..e8cf36ed3e87 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -356,6 +356,7 @@ struct tcf_chain { unsigned int refcnt; unsigned int action_refcnt; bool explicitly_created; + bool flushing; const struct tcf_proto_ops *tmplt_ops; void *tmplt_priv; }; diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 6a576b5ddf93..5701ae20b8fc 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -469,9 +469,12 @@ static void __tcf_chain_put(struct tcf_chain *chain, bool by_act, mutex_unlock(&block->lock); /* The last dropped non-action reference will trigger notification. */ - if (is_last && !by_act) + if (is_last && !by_act) { tc_chain_notify_delete(tmplt_ops, tmplt_priv, chain_index, block, NULL, 0, 0, false); + /* Last reference to chain, no need to lock. */ + chain->flushing = false; + } if (refcnt == 0) { tc_chain_tmplt_del(tmplt_ops, tmplt_priv); @@ -503,6 +506,7 @@ static void tcf_chain_flush(struct tcf_chain *chain) tp = tcf_chain_dereference(chain->filter_chain, chain); RCU_INIT_POINTER(chain->filter_chain, NULL); tcf_chain0_head_change(chain, NULL); + chain->flushing = true; mutex_unlock(&chain->filter_chain_lock); while (tp) { @@ -1602,15 +1606,20 @@ static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain *chain, return tcf_chain_dereference(*chain_info->pprev, chain); } -static void tcf_chain_tp_insert(struct tcf_chain *chain, - struct tcf_chain_info *chain_info, - struct tcf_proto *tp) +static int tcf_chain_tp_insert(struct tcf_chain *chain, + struct tcf_chain_info *chain_info, + struct tcf_proto *tp) { + if (chain->flushing) + return -EAGAIN; + if (*chain_info->pprev == chain->filter_chain) tcf_chain0_head_change(chain, tp); tcf_proto_get(tp); RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain, chain_info)); rcu_assign_pointer(*chain_info->pprev, tp); + + return 0; } static void tcf_chain_tp_remove(struct tcf_chain *chain, @@ -1641,18 +1650,22 @@ static struct tcf_proto *tcf_chain_tp_insert_unique(struct tcf_chain *chain, { struct tcf_chain_info chain_info; struct tcf_proto *tp; + int err = 0; mutex_lock(&chain->filter_chain_lock); tp = tcf_chain_tp_find(chain, &chain_info, protocol, prio, false); if (!tp) - tcf_chain_tp_insert(chain, &chain_info, tp_new); + err = tcf_chain_tp_insert(chain, &chain_info, tp_new); mutex_unlock(&chain->filter_chain_lock); if (tp) { tcf_proto_destroy(tp_new, NULL); tp_new = tp; + } else if (err) { + tcf_proto_destroy(tp_new, NULL); + tp_new = ERR_PTR(err); } return tp_new; @@ -1935,6 +1948,11 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n, if (tp == NULL) { struct tcf_proto *tp_new = NULL; + if (chain->flushing) { + err = -EAGAIN; + goto errout_locked; + } + /* Proto-tcf does not exist, create new one */ if (tca[TCA_KIND] == NULL || !protocol) { @@ -1958,11 +1976,15 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n, protocol, prio, chain, extack); if (IS_ERR(tp_new)) { err = PTR_ERR(tp_new); - goto errout; + goto errout_tp; } tp_created = 1; tp = tcf_chain_tp_insert_unique(chain, tp_new, protocol, prio); + if (IS_ERR(tp)) { + err = PTR_ERR(tp); + goto errout_tp; + } } else { mutex_unlock(&chain->filter_chain_lock); } @@ -2003,6 +2025,7 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n, errout: if (err && tp_created) tcf_chain_tp_delete_empty(chain, tp, NULL); +errout_tp: if (chain) { if (tp && !IS_ERR(tp)) tcf_proto_put(tp, NULL); -- 2.13.6