coresight: etm4x: Ensure valid drvdata and clock before clk_put()

This validates 'drvdata' and 'drvdata->pclk' clock before calling clk_put()
in etm4_remove_platform_dev(). The problem was detected using Smatch static
checker as reported.

Fixes: 73d779a03a76a ("coresight: etm4x: Change etm4_platform_driver driver for MMIO devices")
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/G4N6P4OXELPLLQSNU3GU2MR4LOLRXRMJ/
Reviewed-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@lnaro.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230817035926.157370-1-anshuman.khandual@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 703b6fc..77b0271 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2269,7 +2269,7 @@ static int __exit etm4_remove_platform_dev(struct platform_device *pdev)
                etm4_remove_dev(drvdata);
        pm_runtime_disable(&pdev->dev);
 
-       if (drvdata->pclk)
+       if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
                clk_put(drvdata->pclk);
 
        return 0;