From 068c0a542f6edce90f7d8a9b35a849d990001018 Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Thu, 25 Aug 2016 15:18:56 -0600 Subject: [PATCH] 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 Signed-off-by: Suzuki K Poulose Signed-off-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman --- 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 ceeaaea..bb20ee9 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