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rtc: sa1100: fix possible race condition

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Both RTC IRQs are requested before the struct rtc_device is allocated,
this may lead to a NULL pointer dereference in the IRQ handler.

To fix this issue, allocating the rtc_device struct before requesting
the IRQs using devm_rtc_allocate_device, and use rtc_register_device
to register the RTC device.

Link: https://lore.kernel.org/r/20200306010146.39762-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2020-03-06 02:01:44 +01:00
parent 0a22bd6fe4
commit f2997775b1
1 changed files with 11 additions and 9 deletions
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20
drivers/rtc/rtc-sa1100.c
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@ -182,7 +182,6 @@ static const struct rtc_class_ops sa1100_rtc_ops = {
int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info)
{
struct rtc_device *rtc;
int ret;
spin_lock_init(&info->lock);
@ -211,15 +210,14 @@ int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info)
writel_relaxed(0, info->rcnr);
}
rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &sa1100_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
clk_disable_unprepare(info->clk);
return PTR_ERR(rtc);
}
info->rtc = rtc;
info->rtc->ops = &sa1100_rtc_ops;
info->rtc->max_user_freq = RTC_FREQ;
rtc->max_user_freq = RTC_FREQ;
ret = rtc_register_device(info->rtc);
if (ret) {
clk_disable_unprepare(info->clk);
return ret;
}
/* Fix for a nasty initialization problem the in SA11xx RTSR register.
* See also the comments in sa1100_rtc_interrupt().
@ -267,6 +265,10 @@ static int sa1100_rtc_probe(struct platform_device *pdev)
info->irq_1hz = irq_1hz;
info->irq_alarm = irq_alarm;
info->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(info->rtc))
return PTR_ERR(info->rtc);
ret = devm_request_irq(&pdev->dev, irq_1hz, sa1100_rtc_interrupt, 0,
"rtc 1Hz", &pdev->dev);
if (ret) {