[PATCH] memory: samsung: exynos5422-dmc: Fix refcount leak in of_get_dram_timings

[PATCH] memory: samsung: exynos5422-dmc: Fix refcount leak in of_get_dram_timings

[Miaoqian Lin]

of_parse_phandle() returns a node pointer with refcount
incremented, we should use of_node_put() on it when not need anymore.
This function doesn't call of_node_put() in some error paths.
To unify the structure, Add put_node label and goto it on errors.

Fixes: 6e7674c3c6df ("memory: Add DMC driver for Exynos5422")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
 drivers/memory/samsung/exynos5422-dmc.c | 29 +++++++++++++++----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
index 4733e7898ffe..c491cd549644 100644
--- a/drivers/memory/samsung/exynos5422-dmc.c
+++ b/drivers/memory/samsung/exynos5422-dmc.c
@@ -1187,33 +1187,39 @@ static int of_get_dram_timings(struct exynos5_dmc *dmc)
 
 	dmc->timing_row = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
 					     sizeof(u32), GFP_KERNEL);
-	if (!dmc->timing_row)
-		return -ENOMEM;
+	if (!dmc->timing_row) {
+		ret = -ENOMEM;
+		goto put_node;
+	}
 
 	dmc->timing_data = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
 					      sizeof(u32), GFP_KERNEL);
-	if (!dmc->timing_data)
-		return -ENOMEM;
+	if (!dmc->timing_data) {
+		ret = -ENOMEM;
+		goto put_node;
+	}
 
 	dmc->timing_power = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
 					       sizeof(u32), GFP_KERNEL);
-	if (!dmc->timing_power)
-		return -ENOMEM;
+	if (!dmc->timing_power) {
+		ret = -ENOMEM;
+		goto put_node;
+	}
 
 	dmc->timings = of_lpddr3_get_ddr_timings(np_ddr, dmc->dev,
 						 DDR_TYPE_LPDDR3,
 						 &dmc->timings_arr_size);
 	if (!dmc->timings) {
-		of_node_put(np_ddr);
 		dev_warn(dmc->dev, "could not get timings from DT\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto put_node;
 	}
 
 	dmc->min_tck = of_lpddr3_get_min_tck(np_ddr, dmc->dev);
 	if (!dmc->min_tck) {
-		of_node_put(np_ddr);
 		dev_warn(dmc->dev, "could not get tck from DT\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto put_node;
 	}
 
 	/* Sorted array of OPPs with frequency ascending */
@@ -1227,13 +1233,14 @@ static int of_get_dram_timings(struct exynos5_dmc *dmc)
 					     clk_period_ps);
 	}
 
-	of_node_put(np_ddr);
 
 	/* Take the highest frequency's timings as 'bypass' */
 	dmc->bypass_timing_row = dmc->timing_row[idx - 1];
 	dmc->bypass_timing_data = dmc->timing_data[idx - 1];
 	dmc->bypass_timing_power = dmc->timing_power[idx - 1];
 
+put_node:
+	of_node_put(np_ddr);
 	return ret;
 }
 
-- 
2.25.1

Re: [PATCH] memory: samsung: exynos5422-dmc: Fix refcount leak in of_get_dram_timings

[Lukasz Luba]

On 6/2/22 05:17, Miaoqian Lin wrote:
> of_parse_phandle() returns a node pointer with refcount
> incremented, we should use of_node_put() on it when not need anymore.
> This function doesn't call of_node_put() in some error paths.
> To unify the structure, Add put_node label and goto it on errors.
> 
> Fixes: 6e7674c3c6df ("memory: Add DMC driver for Exynos5422")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>

Thanks for the patch, LGTM.

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Re: [PATCH] memory: samsung: exynos5422-dmc: Fix refcount leak in of_get_dram_timings

[Krzysztof Kozlowski]

On Thu, 2 Jun 2022 08:17:21 +0400, Miaoqian Lin wrote:
> of_parse_phandle() returns a node pointer with refcount
> incremented, we should use of_node_put() on it when not need anymore.
> This function doesn't call of_node_put() in some error paths.
> To unify the structure, Add put_node label and goto it on errors.
> 
> 

Applied, thanks!

[1/1] memory: samsung: exynos5422-dmc: Fix refcount leak in of_get_dram_timings
      https://git.kernel.org/krzk/linux-mem-ctrl/c/1332661e09304b7b8e84e5edc11811ba08d12abe

Best regards,
-- 
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>