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rtc: mt6397: fix possible race condition 

The IRQ is requested before the struct rtc is allocated and registered, but
this struct is used in the IRQ handler. This may lead to a NULL pointer
dereference.

Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc
before requesting the IRQ.

Acked-by: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
hifive-unleashed-5.1
Alexandre Belloni 2018-09-09 22:38:46 +02:00
parent 05a0a34418
commit babab2f864
1 changed files with 8 additions and 5 deletions
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13
drivers/rtc/rtc-mt6397.c
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@ -332,6 +332,10 @@ static int mtk_rtc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
ret = request_threaded_irq(rtc->irq, NULL,
mtk_rtc_irq_handler_thread,
IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
@ -344,11 +348,11 @@ static int mtk_rtc_probe(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 1);
rtc->rtc_dev = rtc_device_register("mt6397-rtc", &pdev->dev,
&mtk_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev)) {
rtc->rtc_dev->ops = &mtk_rtc_ops;
ret = rtc_register_device(rtc->rtc_dev);
if (ret) {
dev_err(&pdev->dev, "register rtc device failed\n");
ret = PTR_ERR(rtc->rtc_dev);
goto out_free_irq;
}
@ -365,7 +369,6 @@ static int mtk_rtc_remove(struct platform_device *pdev)
{
struct mt6397_rtc *rtc = platform_get_drvdata(pdev);
rtc_device_unregister(rtc->rtc_dev);
free_irq(rtc->irq, rtc->rtc_dev);
irq_dispose_mapping(rtc->irq);