drivers/serial/ucc_uart.c: Add of_node_put to avoid memory leak

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>
Acked-by: Timur Tabi <timur@freescale.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
index 3f4848e2174a2c50c6f2216a8862066ec10b3fcd..38a5ef0ae394422ce844c7215d9377441c7f28f0 100644 (file)
--- a/drivers/tty/serial/ucc_uart.c
+++ b/drivers/tty/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)