From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932333AbcEaL6n (ORCPT ); Tue, 31 May 2016 07:58:43 -0400 Received: from foss.arm.com ([217.140.101.70]:58530 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753845AbcEaL5y (ORCPT ); Tue, 31 May 2016 07:57:54 -0400 From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: mathieu.poirier@linaro.org, linux-kernel@vger.kernel.org, Suzuki K Poulose Subject: [PATCH 3/5] coresight: Fix csdev connections initialisation Date: Tue, 31 May 2016 12:57:36 +0100 Message-Id: <1464695858-29284-4-git-send-email-suzuki.poulose@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1464695858-29284-1-git-send-email-suzuki.poulose@arm.com> References: <1464695858-29284-1-git-send-email-suzuki.poulose@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 and csdev->refcnt, 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 --- drivers/hwtracing/coresight/coresight.c | 42 +++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 0fdaaf4..8410420 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -890,7 +890,7 @@ 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) { @@ -908,29 +908,35 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) nr_refcnts = desc->pdata->nr_outport; } - refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL); - if (!refcnts) { - ret = -ENOMEM; - goto err_kzalloc_refcnts; - } + if (nr_refcnts) { + refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL); + if (!refcnts) { + ret = -ENOMEM; + goto err_kzalloc_refcnts; + } - csdev->refcnt = refcnts; + csdev->refcnt = refcnts; + } 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 for this component */ + if (csdev->nr_outport) { + conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL); + if (!conns) { + ret = -ENOMEM; + goto err_kzalloc_conns; + } - csdev->conns = 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; + } csdev->type = desc->type; csdev->subtype = desc->subtype; -- 1.9.1