[PATCH AUTOSEL 4.19 125/205] rtc: mt6397: fix possible race condition

[PATCH AUTOSEL 4.19 125/205] rtc: mt6397: fix possible race condition

[Sasha Levin]

From: Alexandre Belloni <alexandre.belloni@bootlin.com>

[ Upstream commit babab2f86440352d24e76118fdd7d40cab5fd7bf ]

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: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 385f8303bb412..e9a25ec4d434f 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);
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 126/205] rtc: pl030: fix possible race condition

[Sasha Levin]

From: Alexandre Belloni <alexandre.belloni@bootlin.com>

[ Upstream commit c778ec85825dc895936940072aea9fe9037db684 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/rtc/rtc-pl030.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-pl030.c b/drivers/rtc/rtc-pl030.c
index f85a1a93e669f..343bb6ed17839 100644
--- a/drivers/rtc/rtc-pl030.c
+++ b/drivers/rtc/rtc-pl030.c
@@ -112,6 +112,13 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
 		goto err_rtc;
 	}
 
+	rtc->rtc = devm_rtc_allocate_device(&dev->dev);
+	if (IS_ERR(rtc->rtc)) {
+		ret = PTR_ERR(rtc->rtc);
+		goto err_rtc;
+	}
+
+	rtc->rtc->ops = &pl030_ops;
 	rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
 	if (!rtc->base) {
 		ret = -ENOMEM;
@@ -128,12 +135,9 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
 	if (ret)
 		goto err_irq;
 
-	rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
-				       THIS_MODULE);
-	if (IS_ERR(rtc->rtc)) {
-		ret = PTR_ERR(rtc->rtc);
+	ret = rtc_register_device(rtc->rtc);
+	if (ret)
 		goto err_reg;
-	}
 
 	return 0;
 
@@ -154,7 +158,6 @@ static int pl030_remove(struct amba_device *dev)
 	writel(0, rtc->base + RTC_CR);
 
 	free_irq(dev->irq[0], rtc);
-	rtc_device_unregister(rtc->rtc);
 	iounmap(rtc->base);
 	amba_release_regions(dev);
 
-- 
2.20.1