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Groups > linux.kernel > #1470457

[PATCH 06/28] coresight: Fix csdev connections initialisation

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From: Suzuki K Poulose <suzuki.poulose@arm.com>

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>
---
 drivers/hwtracing/coresight/coresight.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index ceeaaea41ed6..bb20ee9747e1 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -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;
-- 
2.7.4

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[PATCH 00/28] coresight: next v4.8-rc3  Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 20/28] coresight: etm-perf: pass struct perf_event to source::enable/disable() Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 03/28] coresight: always use stashed trace id value in etm4_trace_id Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 21/28] coresight: remove duplicated enumeration Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 02/28] coresight-stm: support mmapping channel regions with mmio_addr Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 26/28] coresight: etm4x: configuring include/exclude function Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 17/28] coresight: tmc: Delete an unnecessary check before the function call "kfree" Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 24/28] coresight: etm4x: cleaning up default filter configuration Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 04/28] coresight: Remove erroneous dma_free_coherent in tmc_probe Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 09/28] coresight: Cleanup TMC status check Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 28/28] coresight: etm4x: adding configurable start/stop filtering Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 08/28] coresight: etmv4: Fix ETMv4x peripheral ID table Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 25/28] coresight: etm4x: adding range filter configuration function Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:30 +0200
  [PATCH 16/28] coresight: etm4x: remove duplicated include from coresight-etm4x.c Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:40 +0200
  [PATCH 10/28] coresight: Add better messages for coresight_timeout Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:40 +0200
  [PATCH 14/28] hwtracing: coresight: of_coresight: add missing of_node_put after calling of_parse_phandle Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:40 +0200
  [PATCH 15/28] coresight: Use local coresight_desc instances Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:40 +0200
  [PATCH 13/28] coresight-etm3x: Add ARM ETM 3.5 Cortex-A5 peripheral ID Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:40 +0200
  [PATCH 11/28] coresight: delay initialisation when children are missing Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:50 +0200
  [PATCH 12/28] coresight: add PM runtime calls to coresight_simple_func() Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:50 +0200
  [PATCH 06/28] coresight: Fix csdev connections initialisation Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:50 +0200
  [PATCH 23/28] coresight: etm4x: split default and filter configuration Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-25 23:50 +0200
  [PATCH 07/28] coresight: tmc: Limit the trace to available data Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-26 00:00 +0200
  [PATCH 19/28] coresight: fix handling of ETM trace register access via sysfs Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-26 00:00 +0200
  [PATCH 27/28] coresight: etm4x: adding configurable address range filtering Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-26 00:00 +0200
  [PATCH 01/28] coresight: access conn->child_name only if it's initialised Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-08-26 00:30 +0200
  Re: [PATCH 00/28] coresight: next v4.8-rc3 Greg KH <gregkh@linuxfoundation.org> - 2016-08-31 13:10 +0200

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