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Subject[PATCH] rtc: snvs: fix possible race condition
Date
From: Anson Huang <Anson.Huang@nxp.com>

The RTC IRQ is requested before the struct rtc_device is allocated,
this may lead to a NULL pointer dereference in IRQ handler.

To fix this issue, allocating the rtc_device struct before requesting
the RTC IRQ using devm_rtc_allocate_device, and use rtc_register_device
to register the RTC device.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
drivers/rtc/rtc-snvs.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index 7ee673a2..4f9a107 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -279,6 +279,10 @@ static int snvs_rtc_probe(struct platform_device *pdev)
if (!data)
return -ENOMEM;

+ data->rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(data->rtc))
+ return PTR_ERR(data->rtc);
+
data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");

if (IS_ERR(data->regmap)) {
@@ -343,10 +347,9 @@ static int snvs_rtc_probe(struct platform_device *pdev)
goto error_rtc_device_register;
}

- data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
- &snvs_rtc_ops, THIS_MODULE);
- if (IS_ERR(data->rtc)) {
- ret = PTR_ERR(data->rtc);
+ data->rtc->ops = &snvs_rtc_ops;
+ ret = rtc_register_device(data->rtc);
+ if (ret) {
dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
goto error_rtc_device_register;
}
--
2.7.4
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