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rtc: sunxi: 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>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2018-06-04 14:05:40 +02:00
parent 696fa1d043
commit 29615d03cc
1 changed files with 9 additions and 14 deletions
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23
drivers/rtc/rtc-sunxi.c
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@ -445,6 +445,10 @@ static int sunxi_rtc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, chip);
chip->dev = &pdev->dev;
chip->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(chip->rtc))
return PTR_ERR(chip->rtc);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
chip->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(chip->base))
@ -481,11 +485,12 @@ static int sunxi_rtc_probe(struct platform_device *pdev)
writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +
SUNXI_ALRM_IRQ_STA);
chip->rtc = rtc_device_register("rtc-sunxi", &pdev->dev,
&sunxi_rtc_ops, THIS_MODULE);
if (IS_ERR(chip->rtc)) {
chip->rtc->ops = &sunxi_rtc_ops;
ret = rtc_register_device(chip->rtc);
if (ret) {
dev_err(&pdev->dev, "unable to register device\n");
return PTR_ERR(chip->rtc);
return ret;
}
dev_info(&pdev->dev, "RTC enabled\n");
@ -493,18 +498,8 @@ static int sunxi_rtc_probe(struct platform_device *pdev)
return 0;
}
static int sunxi_rtc_remove(struct platform_device *pdev)
{
struct sunxi_rtc_dev *chip = platform_get_drvdata(pdev);
rtc_device_unregister(chip->rtc);
return 0;
}
static struct platform_driver sunxi_rtc_driver = {
.probe = sunxi_rtc_probe,
.remove = sunxi_rtc_remove,
.driver = {
.name = "sunxi-rtc",
.of_match_table = sunxi_rtc_dt_ids,