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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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