iio: adc: stm32-adc: harden against NULL pointer deref in stm32_adc_probe()

[ Upstream commit 3a23b384e7e3d64d5587ad10729a34d4f761517e ]

of_match_device() may fail and returns a NULL pointer.

In practice there is no known reasonable way to trigger this, but
in case one is added in future, harden the code by adding the check

Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
Link: https://lore.kernel.org/r/tencent_994DA85912C937E3B5405BA960B31ED90A08@qq.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 2f08200..bbd5bdd 100644 (file)
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -708,6 +708,8 @@ static int stm32_adc_probe(struct platform_device *pdev)
        struct stm32_adc_priv *priv;
        struct device *dev = &pdev->dev;
        struct device_node *np = pdev->dev.of_node;
+       const struct of_device_id *of_id;
+
        struct resource *res;
        u32 max_rate;
        int ret;
@@ -720,8 +722,11 @@ static int stm32_adc_probe(struct platform_device *pdev)
                return -ENOMEM;
        platform_set_drvdata(pdev, &priv->common);
 
-       priv->cfg = (const struct stm32_adc_priv_cfg *)
-               of_match_device(dev->driver->of_match_table, dev)->data;
+       of_id = of_match_device(dev->driver->of_match_table, dev);
+       if (!of_id)
+               return -ENODEV;
+
+       priv->cfg = (const struct stm32_adc_priv_cfg *)of_id->data;
        priv->nb_adc_max = priv->cfg->num_adcs;
        spin_lock_init(&priv->common.lock);