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coresight: Fix csdev connections initialisation

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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>
This commit is contained in:
Suzuki K Poulose 2016-08-25 15:18:56 -06:00 committed by Greg Kroah-Hartman
parent 3afd0634a2
commit 068c0a542f
1 changed files with 14 additions and 10 deletions
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24
drivers/hwtracing/coresight/coresight.c
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@ -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) {
@ -922,16 +922,20 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
csdev->nr_inport = desc->pdata->nr_inport;
csdev->nr_outport = desc->pdata->nr_outport;
conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
if (!conns) {
ret = -ENOMEM;
goto err_kzalloc_conns;
}
for (i = 0; i < csdev->nr_outport; i++) {
conns[i].outport = desc->pdata->outports[i];
conns[i].child_name = desc->pdata->child_names[i];
conns[i].child_port = desc->pdata->child_ports[i];
/* 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;
goto err_kzalloc_conns;
}
for (i = 0; i < csdev->nr_outport; i++) {
conns[i].outport = desc->pdata->outports[i];
conns[i].child_name = desc->pdata->child_names[i];
conns[i].child_port = desc->pdata->child_ports[i];
}
}
csdev->conns = conns;