Commit 1a9e0267 authored by Junhao He's avatar Junhao He Committed by Suzuki K Poulose
Browse files

coresight: Fix memory leak in acpi_buffer->pointer 



There are memory leaks reported by kmemleak:
...
unreferenced object 0xffff00213c141000 (size 1024):
  comm "systemd-udevd", pid 2123, jiffies 4294909467 (age 6062.160s)
  hex dump (first 32 bytes):
    04 00 00 00 02 00 00 00 18 10 14 3c 21 00 ff ff  ...........<!...
    00 00 00 00 00 00 00 00 03 00 00 00 10 00 00 00  ................
  backtrace:
    [<000000004b7c9001>] __kmem_cache_alloc_node+0x2f8/0x348
    [<00000000b0fc7ceb>] __kmalloc+0x58/0x108
    [<0000000064ff4695>] acpi_os_allocate+0x2c/0x68
    [<000000007d57d116>] acpi_ut_initialize_buffer+0x54/0xe0
    [<0000000024583908>] acpi_evaluate_object+0x388/0x438
    [<0000000017b2e72b>] acpi_evaluate_object_typed+0xe8/0x240
    [<000000005df0eac2>] coresight_get_platform_data+0x1b4/0x988 [coresight]
...

The ACPI buffer memory (buf.pointer) should be freed. But the buffer
is also used after returning from acpi_get_dsd_graph().
Move the temporary variables buf to acpi_coresight_parse_graph(),
and free it before the function return to prevent memory leak.

Fixes: 76ffa5ab ("coresight: Support for ACPI bindings")
Signed-off-by: default avatarJunhao He <hejunhao3@huawei.com>
Reviewed-by: default avatarJames Clark <james.clark@arm.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230817085937.55590-2-hejunhao3@huawei.com
parent a4621fd1

drivers/hwtracing/coresight/coresight-platform.c

+26 −14
Original line number Diff line number Diff line
@@ -492,19 +492,18 @@ static inline bool acpi_validate_dsd_graph(const union acpi_object *graph) 


/* acpi_get_dsd_graph	- Find the _DSD Graph property for the given device. */

static const union acpi_object *

acpi_get_dsd_graph(struct acpi_device *adev)

acpi_get_dsd_graph(struct acpi_device *adev, struct acpi_buffer *buf)

{

	int i;

	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };

	acpi_status status;

	const union acpi_object *dsd;



	status = acpi_evaluate_object_typed(adev->handle, "_DSD", NULL,

					    &buf, ACPI_TYPE_PACKAGE);

					    buf, ACPI_TYPE_PACKAGE);

	if (ACPI_FAILURE(status))

		return NULL;



	dsd = buf.pointer;

	dsd = buf->pointer;



	/*

	 * _DSD property consists tuples { Prop_UUID, Package() }
@@ -555,12 +554,12 @@ acpi_validate_coresight_graph(const union acpi_object *cs_graph) 
 * returns NULL.

 */

static const union acpi_object *

acpi_get_coresight_graph(struct acpi_device *adev)

acpi_get_coresight_graph(struct acpi_device *adev, struct acpi_buffer *buf)

{

	const union acpi_object *graph_list, *graph;

	int i, nr_graphs;



	graph_list = acpi_get_dsd_graph(adev);

	graph_list = acpi_get_dsd_graph(adev, buf);

	if (!graph_list)

		return graph_list;
@@ -661,22 +660,24 @@ static int acpi_coresight_parse_graph(struct device *dev, 
				      struct acpi_device *adev,

				      struct coresight_platform_data *pdata)

{

	int ret = 0;

	int i, nlinks;

	const union acpi_object *graph;

	struct coresight_connection conn, zero_conn = {};

	struct coresight_connection *new_conn;

	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };



	graph = acpi_get_coresight_graph(adev);

	graph = acpi_get_coresight_graph(adev, &buf);

	/*

	 * There are no graph connections, which is fine for some components.

	 * e.g., ETE

	 */

	if (!graph)

		return 0;

		goto free;



	nlinks = graph->package.elements[2].integer.value;

	if (!nlinks)

		return 0;

		goto free;



	for (i = 0; i < nlinks; i++) {

		const union acpi_object *link = &graph->package.elements[3 + i];
@@ -684,17 +685,28 @@ static int acpi_coresight_parse_graph(struct device *dev, 


		conn = zero_conn;

		dir = acpi_coresight_parse_link(adev, link, &conn);

		if (dir < 0)

			return dir;

		if (dir < 0) {

			ret = dir;

			goto free;

		}



		if (dir == ACPI_CORESIGHT_LINK_MASTER) {

			new_conn = coresight_add_out_conn(dev, pdata, &conn);

			if (IS_ERR(new_conn))

				return PTR_ERR(new_conn);

			if (IS_ERR(new_conn)) {

				ret = PTR_ERR(new_conn);

				goto free;

			}

		}

	}



	return 0;

free:

	/*

	 * When ACPI fails to alloc a buffer, it will free the buffer

	 * created via ACPI_ALLOCATE_BUFFER and set to NULL.

	 * ACPI_FREE can handle NULL pointers, so free it directly.

	 */

	ACPI_FREE(buf.pointer);

	return ret;

}



/*