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rtc: st-lpc: 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: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2018-05-20 14:33:36 +02:00
parent b72252b658
commit d482510fee
1 changed files with 9 additions and 15 deletions
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24
drivers/rtc/rtc-st-lpc.c
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@ -212,6 +212,10 @@ static int st_rtc_probe(struct platform_device *pdev)
if (!rtc)
return -ENOMEM;
rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
spin_lock_init(&rtc->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@ -253,26 +257,17 @@ static int st_rtc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev = rtc_device_register("st-lpc-rtc", &pdev->dev,
&st_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev)) {
rtc->rtc_dev->ops = &st_rtc_ops;
ret = rtc_register_device(rtc->rtc_dev);
if (ret) {
clk_disable_unprepare(rtc->clk);
return PTR_ERR(rtc->rtc_dev);
return ret;
}
return 0;
}
static int st_rtc_remove(struct platform_device *pdev)
{
struct st_rtc *rtc = platform_get_drvdata(pdev);
if (likely(rtc->rtc_dev))
rtc_device_unregister(rtc->rtc_dev);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int st_rtc_suspend(struct device *dev)
{
@ -325,7 +320,6 @@ static struct platform_driver st_rtc_platform_driver = {
.of_match_table = st_rtc_match,
},
.probe = st_rtc_probe,
.remove = st_rtc_remove,
};
module_platform_driver(st_rtc_platform_driver);