netdev - [PATCH net-next v2 04/17] net: sched: protect block->chain0 with block->lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1544523120-4566-5-git-send-email-vladbu@mellanox.com>
Date:   Tue, 11 Dec 2018 12:11:47 +0200
From:   Vlad Buslov <vladbu@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
        davem@...emloft.net, ast@...nel.org, daniel@...earbox.net,
        Vlad Buslov <vladbu@...lanox.com>
Subject: [PATCH net-next v2 04/17] net: sched: protect block->chain0 with block->lock

In order to remove dependency on rtnl lock, use block->lock to protect
chain0 struct from concurrent modification. Rearrange code in chain0
callback add and del functions to only access chain0 when block->lock is
held.

Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
Acked-by: Jiri Pirko <jiri@...lanox.com>
---
 net/sched/cls_api.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 0e1e7f26ee68..c93570384967 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -260,8 +260,11 @@ static void tcf_chain0_head_change(struct tcf_chain *chain,
 
 	if (chain->index)
 		return;
+
+	spin_lock(&block->lock);
 	list_for_each_entry(item, &block->chain0.filter_chain_list, list)
 		tcf_chain_head_change_item(item, tp_head);
+	spin_unlock(&block->lock);
 }
 
 /* Returns true if block can be safely freed. */
@@ -765,8 +768,8 @@ tcf_chain0_head_change_cb_add(struct tcf_block *block,
 			      struct tcf_block_ext_info *ei,
 			      struct netlink_ext_ack *extack)
 {
-	struct tcf_chain *chain0 = block->chain0.chain;
 	struct tcf_filter_chain_list_item *item;
+	struct tcf_chain *chain0;
 
 	item = kmalloc(sizeof(*item), GFP_KERNEL);
 	if (!item) {
@@ -775,9 +778,14 @@ tcf_chain0_head_change_cb_add(struct tcf_block *block,
 	}
 	item->chain_head_change = ei->chain_head_change;
 	item->chain_head_change_priv = ei->chain_head_change_priv;
+
+	spin_lock(&block->lock);
+	chain0 = block->chain0.chain;
 	if (chain0 && chain0->filter_chain)
 		tcf_chain_head_change_item(item, chain0->filter_chain);
 	list_add(&item->list, &block->chain0.filter_chain_list);
+	spin_unlock(&block->lock);
+
 	return 0;
 }
 
@@ -785,20 +793,23 @@ static void
 tcf_chain0_head_change_cb_del(struct tcf_block *block,
 			      struct tcf_block_ext_info *ei)
 {
-	struct tcf_chain *chain0 = block->chain0.chain;
 	struct tcf_filter_chain_list_item *item;
 
+	spin_lock(&block->lock);
 	list_for_each_entry(item, &block->chain0.filter_chain_list, list) {
 		if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
 		    (item->chain_head_change == ei->chain_head_change &&
 		     item->chain_head_change_priv == ei->chain_head_change_priv)) {
-			if (chain0)
+			if (block->chain0.chain)
 				tcf_chain_head_change_item(item, NULL);
 			list_del(&item->list);
+			spin_unlock(&block->lock);
+
 			kfree(item);
 			return;
 		}
 	}
+	spin_unlock(&block->lock);
 	WARN_ON(1);
 }
 
-- 
2.7.5