netdev - [PATCH] Bluetooth: Make sure LE create conn cancel is sent when timeout

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Message-ID: <20230203173900.1.I9ca803e2f809e339da43c103860118e7381e4871@changeid>
Date:   Fri,  3 Feb 2023 17:39:36 +0800
From:   Archie Pusaka <apusaka@...gle.com>
To:     linux-bluetooth <linux-bluetooth@...r.kernel.org>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        Marcel Holtmann <marcel@...tmann.org>
Cc:     CrosBT Upstreaming <chromeos-bluetooth-upstreaming@...omium.org>,
        Archie Pusaka <apusaka@...omium.org>,
        Ying Hsu <yinghsu@...omium.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH] Bluetooth: Make sure LE create conn cancel is sent when timeout

From: Archie Pusaka <apusaka@...omium.org>

When sending LE create conn command, we set a timer with a duration of
HCI_LE_CONN_TIMEOUT before timing out and calling
create_le_conn_complete. Additionally, when receiving the command
complete, we also set a timer with the same duration to call
le_conn_timeout.

Usually the latter will be triggered first, which then sends a LE
create conn cancel command. However, due to the nature of racing, it
is possible for the former to be called first, thereby calling the
chain hci_conn_failed -> hci_conn_del -> cancel_delayed_work, thereby
preventing LE create conn cancel to be sent. In this situation, the
controller will be stuck in trying the LE connection.

This patch flushes le_conn_timeout on create_le_conn_complete to make
sure we always send LE create connection cancel, if necessary.

Signed-off-by: Archie Pusaka <apusaka@...omium.org>
Reviewed-by: Ying Hsu <yinghsu@...omium.org>

---

 net/bluetooth/hci_conn.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 61a34801e61e..f2c7edaa7145 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1243,6 +1243,8 @@ static void create_le_conn_complete(struct hci_dev *hdev, void *data, int err)
 	if (conn != hci_lookup_le_connect(hdev))
 		goto done;

+	/* Flush to make sure we send create conn cancel command if needed */
+	flush_delayed_work(&conn->le_conn_timeout);
 	hci_conn_failed(conn, bt_status(err));

 done:
-- 
2.39.1.519.gcb327c4b5f-goog