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From:   Vignesh Viswanathan <quic_viswanat@quicinc.com>
To:     <mani@kernel.org>, <davem@davemloft.net>, <edumazet@google.com>,
        <kuba@kernel.org>, <pabeni@redhat.com>,
        <linux-arm-msm@vger.kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     <quic_srichara@quicinc.com>, <quic_clew@quicinc.com>,
        Vignesh Viswanathan <quic_viswanat@quicinc.com>
Subject: [PATCH net-next 2/3] net: qrtr: ns: Change nodes radix tree to xarray
Date:   Wed, 12 Jul 2023 16:56:30 +0530
Message-ID: <20230712112631.3461793-3-quic_viswanat@quicinc.com>
In-Reply-To: <20230712112631.3461793-1-quic_viswanat@quicinc.com>
References: <20230712112631.3461793-1-quic_viswanat@quicinc.com>
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There is a use after free scenario while iterating through the nodes
radix tree despite the ns being a single threaded process. This can
happen when the radix tree APIs are not synchronized with the
rcu_read_lock() APIs.

Convert the radix tree for nodes to xarray to take advantage of the
built in rcu lock usage provided by xarray.

Signed-off-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Vignesh Viswanathan <quic_viswanat@quicinc.com>
---
 net/qrtr/ns.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index 039313c3e044..12de671d7992 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -16,7 +16,7 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/qrtr.h>
 
-static RADIX_TREE(nodes, GFP_KERNEL);
+static DEFINE_XARRAY(nodes);
 
 static struct {
 	struct socket *sock;
@@ -73,7 +73,7 @@ static struct qrtr_node *node_get(unsigned int node_id)
 {
 	struct qrtr_node *node;
 
-	node = radix_tree_lookup(&nodes, node_id);
+	node = xa_load(&nodes, node_id);
 	if (node)
 		return node;
 
@@ -85,7 +85,7 @@ static struct qrtr_node *node_get(unsigned int node_id)
 	node->id = node_id;
 	xa_init(&node->servers);
 
-	if (radix_tree_insert(&nodes, node_id, node)) {
+	if (xa_store(&nodes, node_id, node, GFP_KERNEL)) {
 		kfree(node);
 		return NULL;
 	}
-- 
2.41.0