diff mbox series

[1/2] coresight: etm3x: Smatch: Fix potential NULL pointer dereference

Message ID 20190621175205.24551-2-mathieu.poirier@linaro.org (mailing list archive)
State Mainlined
Commit 020601622323d02e09cebe05e7976b3d4b44e05d
Headers show
Series coresight: next v5.2-rc5 (Part 2) | expand

Commit Message

Mathieu Poirier June 21, 2019, 5:52 p.m. UTC 
From: Suzuki K Poulose <suzuki.poulose@arm.com>

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 <mathieu.poirier@linaro.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm3x.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index bed729140718..225c2982e4fe 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;