Commit 068c0a54 authored Aug 25, 2016 by Suzuki K Poulose Committed by Greg Kroah-Hartman Aug 31, 2016

coresight: Fix csdev connections initialisation



This is a cleanup patch.

coresight_device->conns holds an array to point to the devices
connected to the OUT ports of a component. Sinks, e.g ETR, do not
have an OUT port (nr_outport = 0), as it streams the trace to
memory via AXI.

At coresight_register() we do :

	conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
	if (!conns) {
		ret = -ENOMEM;
		goto err_kzalloc_conns;
	}

For ETR, since the total size requested for kcalloc is zero, the return
value is, ZERO_SIZE_PTR ( != NULL). Hence, csdev->conns = ZERO_SIZE_PTR
which cannot be verified later to contain a valid pointer. The code which
accesses the csdev->conns is bounded by the csdev->nr_outport check,
hence we don't try to dereference the ZERO_SIZE_PTR. This patch cleans
up the csdev->conns initialisation to make sure we initialise it
properly(i.e, either NULL or valid conns array).

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 3afd0634

drivers/hwtracing/coresight/coresight.c

+14 −10

Original line number	Diff line number	Diff line
		@@ -894,7 +894,7 @@ struct coresight_device coresight_register(struct coresight_desc desc)
		int nr_refcnts = 1;
		atomic_t *refcnts = NULL;
		struct coresight_device *csdev;
		struct coresight_connection *conns;
		struct coresight_connection *conns = NULL;

		csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
		if (!csdev) {
		@@ -922,6 +922,9 @@ struct coresight_device coresight_register(struct coresight_desc desc)

		csdev->nr_inport = desc->pdata->nr_inport;
		csdev->nr_outport = desc->pdata->nr_outport;

		/* Initialise connections if there is at least one outport */
		if (csdev->nr_outport) {
		conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
		if (!conns) {
		ret = -ENOMEM;
		@@ -933,6 +936,7 @@ struct coresight_device coresight_register(struct coresight_desc desc)
		conns[i].child_name = desc->pdata->child_names[i];
		conns[i].child_port = desc->pdata->child_ports[i];
		}
		}

		csdev->conns = conns;