From 020601622323d02e09cebe05e7976b3d4b44e05d Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Fri, 21 Jun 2019 11:52:04 -0600 Subject: [PATCH] coresight: etm3x: Smatch: Fix potential NULL pointer dereference Based on the following report from Smatch tool, make sure we have a valid drvdata before we dereference it to find the real dev. The patch 21d26b905c05: "coresight: etm: Clean up device specific data" from May 22, 2019, leads to the following Smatch complaint: ./drivers/hwtracing/coresight/coresight-etm3x.c:460 etm_get_trace_id() warn: variable dereferenced before check 'drvdata' (see line 458) ./drivers/hwtracing/coresight/coresight-etm3x.c 457 int trace_id = -1; 458 struct device *etm_dev = drvdata->csdev->dev.parent; ^^^^^^^^^ New dereference 459 460 if (!drvdata) ^^^^^^^^ Checked too late. Delete the check? 461 goto out; 462 Cc: Mathieu Poirier Cc: Dan Carpenter Signed-off-by: Suzuki K Poulose Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20190621175205.24551-2-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-etm3x.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c index bed7291..225c298 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x.c +++ b/drivers/hwtracing/coresight/coresight-etm3x.c @@ -455,11 +455,12 @@ int etm_get_trace_id(struct etm_drvdata *drvdata) { unsigned long flags; int trace_id = -1; - struct device *etm_dev = drvdata->csdev->dev.parent; + struct device *etm_dev; if (!drvdata) goto out; + etm_dev = drvdata->csdev->dev.parent; if (!local_read(&drvdata->mode)) return drvdata->traceid; -- 2.7.4