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From: Florian Westphal <fw@strlen.de>
To: <netfilter-devel@vger.kernel.org>
Cc: Florian Westphal <fw@strlen.de>
Subject: [PATCH nf-next v4 1/5] netfilter: nf_conncount: callers must hold rcu read lock
Date: Fri,  5 Jun 2026 15:11:19 +0200	[thread overview]
Message-ID: <20260605131123.19435-2-fw@strlen.de> (raw)
In-Reply-To: <20260605131123.19435-1-fw@strlen.de>

rcu_derefence_raw() should not have been used here, it concealed this bug.
Its used because struct rb_node lacks __rcu annotated pointers, so plain
rcu_derefence causes sparse warnings.

The major tradeoff is that rcu_derefence_raw() doesn't warn when the caller
isn't in a rcu read section.

Extend the rcu read lock scope accordingly and cause sparse warnings,
those warnings are the lesser evil.

Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
Closes: https://sashiko.dev/#/patchset/20260603230610.7900-1-fw%40strlen.de
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 v4: no changes.

 net/netfilter/nf_conncount.c | 6 +++---
 net/openvswitch/conntrack.c  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index ab28b47395bd..81e4a4e20df5 100644
--- a/net/netfilter/nf_conncount.c
+++ b/net/netfilter/nf_conncount.c
@@ -499,7 +499,7 @@ count_tree(struct net *net,
 	hash = jhash2(key, data->keylen, data->initval) % CONNCOUNT_SLOTS;
 	root = &data->root[hash];
 
-	parent = rcu_dereference_raw(root->rb_node);
+	parent = rcu_dereference(root->rb_node);
 	while (parent) {
 		int diff;
 
@@ -507,9 +507,9 @@ count_tree(struct net *net,
 
 		diff = key_diff(key, rbconn->key, data->keylen);
 		if (diff < 0) {
-			parent = rcu_dereference_raw(parent->rb_left);
+			parent = rcu_dereference(parent->rb_left);
 		} else if (diff > 0) {
-			parent = rcu_dereference_raw(parent->rb_right);
+			parent = rcu_dereference(parent->rb_right);
 		} else {
 			int ret;
 
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 7c9256572284..c6fd9c424e8f 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -1797,10 +1797,10 @@ static int ovs_ct_limit_get_zone_limit(struct net *net,
 		} else {
 			rcu_read_lock();
 			limit = ct_limit_get(info, zone);
-			rcu_read_unlock();
 
 			err = __ovs_ct_limit_get_zone_limit(
 				net, info->data, zone, limit, reply);
+			rcu_read_unlock();
 			if (err)
 				return err;
 		}
-- 
2.53.0


  reply	other threads:[~2026-06-05 13:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-05 13:11 [PATCH nf-next v4 0/5] netfilter: nf_conncount: fix gc and rbtree bugs Florian Westphal
2026-06-05 13:11 ` Florian Westphal [this message]
2026-06-05 13:11 ` [PATCH nf-next v4 2/5] netfilter: nf_conncount: use per nf_conncount_data spinlocks Florian Westphal
2026-06-05 14:40   ` Florian Westphal
2026-06-05 13:11 ` [PATCH nf-next v4 3/5] netfilter: nf_conncount: split count_tree_node rbtree walk into helper Florian Westphal
2026-06-05 13:11 ` [PATCH nf-next v4 4/5] netfilter: nf_conncount: add sequence counter to detect tree modifications Florian Westphal
2026-06-05 13:11 ` [PATCH nf-next v4 5/5] netfilter: nf_conncount: gc and rcu fixes Florian Westphal

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