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Commit 5a869e98 authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Greg Kroah-Hartman
Browse files

rtc: mt6397: fix possible race condition 



[ Upstream commit babab2f86440352d24e76118fdd7d40cab5fd7bf ]

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: default avatarEddie Huang <eddie.huang@mediatek.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0773f03a

drivers/rtc/rtc-mt6397.c

+8 −5
Original line number Diff line number Diff line
@@ -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);