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rtc: pl030: 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.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2018-09-09 22:38:47 +02:00
parent babab2f864
commit c778ec8582
1 changed files with 9 additions and 6 deletions
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15
drivers/rtc/rtc-pl030.c
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@ -112,6 +112,13 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
goto err_rtc;
}
rtc->rtc = devm_rtc_allocate_device(&dev->dev);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
goto err_rtc;
}
rtc->rtc->ops = &pl030_ops;
rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
if (!rtc->base) {
ret = -ENOMEM;
@ -128,12 +135,9 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
if (ret)
goto err_irq;
rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
ret = rtc_register_device(rtc->rtc);
if (ret)
goto err_reg;
}
return 0;
@ -154,7 +158,6 @@ static int pl030_remove(struct amba_device *dev)
writel(0, rtc->base + RTC_CR);
free_irq(dev->irq[0], rtc);
rtc_device_unregister(rtc->rtc);
iounmap(rtc->base);
amba_release_regions(dev);