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rtc: mxc: 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.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
hifive-unleashed-5.2
Alexandre Belloni 2019-04-16 10:30:43 +02:00
parent cf612c5949
commit ebc2ec4ecf
1 changed files with 9 additions and 7 deletions
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16
drivers/rtc/rtc-mxc.c
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@ -340,6 +340,13 @@ static int mxc_rtc_probe(struct platform_device *pdev)
if (IS_ERR(pdata->ioaddr))
return PTR_ERR(pdata->ioaddr);
rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
pdata->rtc = rtc;
rtc->ops = &mxc_rtc_ops;
pdata->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
if (IS_ERR(pdata->clk_ipg)) {
dev_err(&pdev->dev, "unable to get ipg clock!\n");
@ -402,14 +409,9 @@ static int mxc_rtc_probe(struct platform_device *pdev)
dev_err(&pdev->dev, "failed to enable irq wake\n");
}
rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &mxc_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
ret = rtc_register_device(rtc);
if (ret)
goto exit_put_clk_ref;
}
pdata->rtc = rtc;
return 0;