| Message ID | 20180909203848.3470-1-alexandre.belloni@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/3] rtc: mt6397: fix possible race condition | expand |
On Sun, 2018-09-09 at 22:38 +0200, Alexandre Belloni wrote: > 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. > > Cc: Eddie Huang <eddie.huang@mediatek.com> > Cc: Sean Wang <sean.wang@mediatek.com> > Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> > --- > drivers/rtc/rtc-mt6397.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c > index 385f8303bb41..e9a25ec4d434 100644 > --- a/drivers/rtc/rtc-mt6397.c > +++ b/drivers/rtc/rtc-mt6397.c > @@ -332,6 +332,10 @@ static int mtk_rtc_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, rtc); > > + rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev); > + if (IS_ERR(rtc->rtc_dev)) > + return PTR_ERR(rtc->rtc_dev); > + > ret = request_threaded_irq(rtc->irq, NULL, > mtk_rtc_irq_handler_thread, > IRQF_ONESHOT | IRQF_TRIGGER_HIGH, > @@ -344,11 +348,11 @@ static int mtk_rtc_probe(struct platform_device *pdev) > > device_init_wakeup(&pdev->dev, 1); > > - rtc->rtc_dev = rtc_device_register("mt6397-rtc", &pdev->dev, > - &mtk_rtc_ops, THIS_MODULE); > - if (IS_ERR(rtc->rtc_dev)) { > + rtc->rtc_dev->ops = &mtk_rtc_ops; > + > + ret = rtc_register_device(rtc->rtc_dev); > + if (ret) { > dev_err(&pdev->dev, "register rtc device failed\n"); > - ret = PTR_ERR(rtc->rtc_dev); > goto out_free_irq; > } > > @@ -365,7 +369,6 @@ static int mtk_rtc_remove(struct platform_device *pdev) > { > struct mt6397_rtc *rtc = platform_get_drvdata(pdev); > > - rtc_device_unregister(rtc->rtc_dev); > free_irq(rtc->irq, rtc->rtc_dev); > irq_dispose_mapping(rtc->irq); > Thanks Acked-by: Eddie Huang <eddie.huang@mediatek.com>
diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c index 385f8303bb41..e9a25ec4d434 100644 --- a/drivers/rtc/rtc-mt6397.c +++ b/drivers/rtc/rtc-mt6397.c @@ -332,6 +332,10 @@ static int mtk_rtc_probe(struct platform_device *pdev) platform_set_drvdata(pdev, rtc); + rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + ret = request_threaded_irq(rtc->irq, NULL, mtk_rtc_irq_handler_thread, IRQF_ONESHOT | IRQF_TRIGGER_HIGH, @@ -344,11 +348,11 @@ static int mtk_rtc_probe(struct platform_device *pdev) device_init_wakeup(&pdev->dev, 1); - rtc->rtc_dev = rtc_device_register("mt6397-rtc", &pdev->dev, - &mtk_rtc_ops, THIS_MODULE); - if (IS_ERR(rtc->rtc_dev)) { + rtc->rtc_dev->ops = &mtk_rtc_ops; + + ret = rtc_register_device(rtc->rtc_dev); + if (ret) { dev_err(&pdev->dev, "register rtc device failed\n"); - ret = PTR_ERR(rtc->rtc_dev); goto out_free_irq; } @@ -365,7 +369,6 @@ static int mtk_rtc_remove(struct platform_device *pdev) { struct mt6397_rtc *rtc = platform_get_drvdata(pdev); - rtc_device_unregister(rtc->rtc_dev); free_irq(rtc->irq, rtc->rtc_dev); irq_dispose_mapping(rtc->irq);
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. Cc: Eddie Huang <eddie.huang@mediatek.com> Cc: Sean Wang <sean.wang@mediatek.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> --- drivers/rtc/rtc-mt6397.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)