Bluetooth: Fix locking of hdev when calling into SMP code

The SMP code expects hdev to be unlocked since e.g. crypto functions
will try to (re)lock it. Therefore, we need to release the lock before
calling into smp.c from mgmt.c. Without this we risk a deadlock whenever
the smp_user_confirm_reply() function is called.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Tested-by: Lukasz Rymanowski <lukasz.rymanowski@tieto.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 6107e037cd8e19a0af7ea3d7c7dbc6bdda5bd1c4..af8e0a6243b7520617156f79d7d430ce12ef4be9 100644 (file)
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3031,8 +3031,13 @@ static int user_pairing_resp(struct sock *sk, struct hci_dev *hdev,
        }
 
        if (addr->type == BDADDR_LE_PUBLIC || addr->type == BDADDR_LE_RANDOM) {
-               /* Continue with pairing via SMP */
+               /* Continue with pairing via SMP. The hdev lock must be
+                * released as SMP may try to recquire it for crypto
+                * purposes.
+                */
+               hci_dev_unlock(hdev);
                err = smp_user_confirm_reply(conn, mgmt_op, passkey);
+               hci_dev_lock(hdev);
 
                if (!err)
                        err = cmd_complete(sk, hdev->id, mgmt_op,