rtc: digicolor: 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
struct before requesting the IRQ.

Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/rtc-digicolor.c b/drivers/rtc/rtc-digicolor.c
index b253bf1b35314776ee3df0b9fc68c7c2f544ce78..5bb14c56bc9a097fb67f82fdfc13a0ca33ac4132 100644 (file)
--- a/drivers/rtc/rtc-digicolor.c
+++ b/drivers/rtc/rtc-digicolor.c
@@ -192,6 +192,10 @@ static int __init dc_rtc_probe(struct platform_device *pdev)
        if (IS_ERR(rtc->regs))
                return PTR_ERR(rtc->regs);
 
+       rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+       if (IS_ERR(rtc->rtc_dev))
+               return PTR_ERR(rtc->rtc_dev);
+
        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;
@@ -200,12 +204,10 @@ static int __init dc_rtc_probe(struct platform_device *pdev)
                return ret;
 
        platform_set_drvdata(pdev, rtc);
-       rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
-                                               &dc_rtc_ops, THIS_MODULE);
-       if (IS_ERR(rtc->rtc_dev))
-               return PTR_ERR(rtc->rtc_dev);
 
-       return 0;
+       rtc->rtc_dev->ops = &dc_rtc_ops;
+
+       return rtc_register_device(rtc->rtc_dev);
 }
 
 static const struct of_device_id dc_dt_ids[] = {