linux-kernel - [PATCH v2] hwrng: exynos - fix reference leak in exynos_trng

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Date:   Mon, 30 Nov 2020 21:01:18 +0800
From:   Qinglang Miao <miaoqinglang@...wei.com>
To:     Łukasz Stelmach <l.stelmach@...sung.com>,
        "Krzysztof Kozlowski" <krzk@...nel.org>
CC:     <linux-samsung-soc@...r.kernel.org>,
        <linux-crypto@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Qinglang Miao <miaoqinglang@...wei.com>
Subject: [PATCH v2] hwrng: exynos - fix reference leak in exynos_trng_probe

pm_runtime_get_sync will increment pm usage counter even
failed. Forgetting to putting operation will result in a
reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage
counter balanced. I remove err_clock label at the same.

Fixes: 6cd225cc5d8a ("hwrng: exynos - add Samsung Exynos True RNG driver")
Reported-by: Hulk Robot <hulkci@...wei.com>
Suggested-by: Lukasz Stelmach <l.stelmach@...sung.com>
Signed-off-by: Qinglang Miao <miaoqinglang@...wei.com>
---
 v2: remobe useless label as Lukasz suggested.

 drivers/char/hw_random/exynos-trng.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/char/hw_random/exynos-trng.c b/drivers/char/hw_random/exynos-trng.c
index 8e1fe3f8d..ffebb72e4 100644
--- a/drivers/char/hw_random/exynos-trng.c
+++ b/drivers/char/hw_random/exynos-trng.c
@@ -132,7 +132,7 @@ static int exynos_trng_probe(struct platform_device *pdev)
 		return PTR_ERR(trng->mem);
 
 	pm_runtime_enable(&pdev->dev);
-	ret = pm_runtime_get_sync(&pdev->dev);
+	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Could not get runtime PM.\n");
 		goto err_pm_get;
@@ -142,13 +142,13 @@ static int exynos_trng_probe(struct platform_device *pdev)
 	if (IS_ERR(trng->clk)) {
 		ret = PTR_ERR(trng->clk);
 		dev_err(&pdev->dev, "Could not get clock.\n");
-		goto err_clock;
+		goto err_pm_get;
 	}
 
 	ret = clk_prepare_enable(trng->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not enable the clk.\n");
-		goto err_clock;
+		goto err_pm_get;
 	}
 
 	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
@@ -164,9 +164,6 @@ static int exynos_trng_probe(struct platform_device *pdev)
 err_register:
 	clk_disable_unprepare(trng->clk);
 
-err_clock:
-	pm_runtime_put_sync(&pdev->dev);
-
 err_pm_get:
 	pm_runtime_disable(&pdev->dev);
 
-- 
2.23.0