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    Subject[PATCH 1/4] drivers/serial/ucc_uart.c: Add of_node_put to avoid memory leak
    Date
    Add a call to of_node_put in the error handling code following a call to
    of_find_compatible_node or of_find_node_by_type.

    This patch also substantially reorganizes the error handling code in the
    function, to that it is possible first to jump to code that frees qe_port
    and then to jump to code that also puts np.

    The semantic match that finds this problem is as follows:
    (http://coccinelle.lip6.fr/)

    // <smpl>
    @r exists@
    local idexpression x;
    expression E,E1,E2;
    statement S;
    @@

    *x =
    (of_find_node_by_path
    |of_find_node_by_name
    |of_find_node_by_phandle
    |of_get_parent
    |of_get_next_parent
    |of_get_next_child
    |of_find_compatible_node
    |of_match_node
    |of_find_node_by_type
    |of_find_node_with_property
    |of_find_matching_node
    |of_parse_phandle
    )(...);
    ...
    if (x == NULL) S
    <... when != x = E
    *if (...) {
    ... when != of_node_put(x)
    when != if (...) { ... of_node_put(x); ... }
    (
    return <+...x...+>;
    |
    * return ...;
    )
    }
    ...>
    (
    E2 = x;
    |
    of_node_put(x);
    )
    // </smpl>

    Signed-off-by: Julia Lawall <julia@diku.dk>

    ---
    drivers/serial/ucc_uart.c | 67 ++++++++++++++++++++++++----------------------
    1 file changed, 35 insertions(+), 32 deletions(-)

    diff --git a/drivers/serial/ucc_uart.c b/drivers/serial/ucc_uart.c
    index 3f4848e..38a5ef0 100644
    --- a/drivers/serial/ucc_uart.c
    +++ b/drivers/serial/ucc_uart.c
    @@ -1270,13 +1270,12 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    ret = of_address_to_resource(np, 0, &res);
    if (ret) {
    dev_err(&ofdev->dev, "missing 'reg' property in device tree\n");
    - kfree(qe_port);
    - return ret;
    + goto out_free;
    }
    if (!res.start) {
    dev_err(&ofdev->dev, "invalid 'reg' property in device tree\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }
    qe_port->port.mapbase = res.start;

    @@ -1286,17 +1285,17 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    if (!iprop) {
    iprop = of_get_property(np, "device-id", NULL);
    if (!iprop) {
    - kfree(qe_port);
    dev_err(&ofdev->dev, "UCC is unspecified in "
    "device tree\n");
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }
    }

    if ((*iprop < 1) || (*iprop > UCC_MAX_NUM)) {
    dev_err(&ofdev->dev, "no support for UCC%u\n", *iprop);
    - kfree(qe_port);
    - return -ENODEV;
    + ret = -ENODEV;
    + goto out_free;
    }
    qe_port->ucc_num = *iprop - 1;

    @@ -1310,16 +1309,16 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    sprop = of_get_property(np, "rx-clock-name", NULL);
    if (!sprop) {
    dev_err(&ofdev->dev, "missing rx-clock-name in device tree\n");
    - kfree(qe_port);
    - return -ENODEV;
    + ret = -ENODEV;
    + goto out_free;
    }

    qe_port->us_info.rx_clock = qe_clock_source(sprop);
    if ((qe_port->us_info.rx_clock < QE_BRG1) ||
    (qe_port->us_info.rx_clock > QE_BRG16)) {
    dev_err(&ofdev->dev, "rx-clock-name must be a BRG for UART\n");
    - kfree(qe_port);
    - return -ENODEV;
    + ret = -ENODEV;
    + goto out_free;
    }

    #ifdef LOOPBACK
    @@ -1329,39 +1328,39 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    sprop = of_get_property(np, "tx-clock-name", NULL);
    if (!sprop) {
    dev_err(&ofdev->dev, "missing tx-clock-name in device tree\n");
    - kfree(qe_port);
    - return -ENODEV;
    + ret = -ENODEV;
    + goto out_free;
    }
    qe_port->us_info.tx_clock = qe_clock_source(sprop);
    #endif
    if ((qe_port->us_info.tx_clock < QE_BRG1) ||
    (qe_port->us_info.tx_clock > QE_BRG16)) {
    dev_err(&ofdev->dev, "tx-clock-name must be a BRG for UART\n");
    - kfree(qe_port);
    - return -ENODEV;
    + ret = -ENODEV;
    + goto out_free;
    }

    /* Get the port number, numbered 0-3 */
    iprop = of_get_property(np, "port-number", NULL);
    if (!iprop) {
    dev_err(&ofdev->dev, "missing port-number in device tree\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }
    qe_port->port.line = *iprop;
    if (qe_port->port.line >= UCC_MAX_UART) {
    dev_err(&ofdev->dev, "port-number must be 0-%u\n",
    UCC_MAX_UART - 1);
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }

    qe_port->port.irq = irq_of_parse_and_map(np, 0);
    if (qe_port->port.irq == NO_IRQ) {
    dev_err(&ofdev->dev, "could not map IRQ for UCC%u\n",
    qe_port->ucc_num + 1);
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }

    /*
    @@ -1373,8 +1372,8 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    np = of_find_node_by_type(NULL, "qe");
    if (!np) {
    dev_err(&ofdev->dev, "could not find 'qe' node\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_free;
    }
    }

    @@ -1382,8 +1381,8 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    if (!iprop) {
    dev_err(&ofdev->dev,
    "missing brg-frequency in device tree\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_np;
    }

    if (*iprop)
    @@ -1398,16 +1397,16 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    if (!iprop) {
    dev_err(&ofdev->dev,
    "missing QE bus-frequency in device tree\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_np;
    }
    if (*iprop)
    qe_port->port.uartclk = *iprop / 2;
    else {
    dev_err(&ofdev->dev,
    "invalid QE bus-frequency in device tree\n");
    - kfree(qe_port);
    - return -EINVAL;
    + ret = -EINVAL;
    + goto out_np;
    }
    }

    @@ -1445,8 +1444,7 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    if (ret) {
    dev_err(&ofdev->dev, "could not add /dev/ttyQE%u\n",
    qe_port->port.line);
    - kfree(qe_port);
    - return ret;
    + goto out_np;
    }

    dev_set_drvdata(&ofdev->dev, qe_port);
    @@ -1460,6 +1458,11 @@ static int ucc_uart_probe(struct platform_device *ofdev,
    SERIAL_QE_MINOR + qe_port->port.line);

    return 0;
    +out_np:
    + of_node_put(np);
    +out_free:
    + kfree(qe_port);
    + return ret;
    }

    static int ucc_uart_remove(struct platform_device *ofdev)


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